update

backend/.env

@@ -0,0 +1,14 @@
+PORT=8080
+DATABASE_URL=postgres://postgres:Timmy0104199%3F@localhost:5432/teg?sslmode=disable
+JWT_SECRET=tegvideo7010!
+FRONTEND_ORIGIN=http://localhost:5173
+
+ADMIN_USERNAME=admin
+ADMIN_DISPLAY_NAME=Administrator
+ADMIN_EMAIL=admin@example.com
+ADMIN_UNIT=Administration
+ADMIN_GROUP=admin
+ADMIN_RIGHTS=admin,users:read,users:write
+ADMIN_TEAM_NAME=Administration
+ADMIN_TEAM_INITIAL=A
+ADMIN_TEAM_HREF=#

backend/cors.go

@@ -0,0 +1,25 @@
+// backend\cors.go
+
+package main
+
+import "net/http"
+
+func (s *Server) cors(next http.Handler) http.Handler {
+	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		origin := r.Header.Get("Origin")
+
+		if origin == s.frontendOrigin {
+			w.Header().Set("Access-Control-Allow-Origin", s.frontendOrigin)
+			w.Header().Set("Access-Control-Allow-Credentials", "true")
+			w.Header().Set("Access-Control-Allow-Headers", "Content-Type")
+			w.Header().Set("Access-Control-Allow-Methods", "GET, POST, PUT, OPTIONS")
+		}
+
+		if r.Method == http.MethodOptions {
+			w.WriteHeader(http.StatusNoContent)
+			return
+		}
+
+		next.ServeHTTP(w, r)
+	})
+}

backend/devices.go

@@ -0,0 +1,561 @@
+// backend/devices.go
+
+package main
+
+import (
+	"context"
+	"errors"
+	"net/http"
+	"strings"
+	"time"
+
+	"github.com/jackc/pgx/v5"
+	"github.com/jackc/pgx/v5/pgconn"
+)
+
+type Device struct {
+	ID              string        `json:"id"`
+	InventoryNumber string        `json:"inventoryNumber"`
+	Manufacturer    string        `json:"manufacturer"`
+	Model           string        `json:"model"`
+	SerialNumber    string        `json:"serialNumber"`
+	MacAddress      string        `json:"macAddress"`
+	Location        string        `json:"location"`
+	LoanStatus      string        `json:"loanStatus"`
+	Comment         string        `json:"comment"`
+	RelatedDevices  []DeviceShort `json:"relatedDevices"`
+	CreatedAt       time.Time     `json:"createdAt"`
+	UpdatedAt       time.Time     `json:"updatedAt"`
+}
+
+type DeviceShort struct {
+	ID              string `json:"id"`
+	InventoryNumber string `json:"inventoryNumber"`
+	Manufacturer    string `json:"manufacturer"`
+	Model           string `json:"model"`
+}
+
+type CreateDeviceRequest struct {
+	InventoryNumber  string   `json:"inventoryNumber"`
+	Manufacturer     string   `json:"manufacturer"`
+	Model            string   `json:"model"`
+	SerialNumber     string   `json:"serialNumber"`
+	MacAddress       string   `json:"macAddress"`
+	Location         string   `json:"location"`
+	LoanStatus       string   `json:"loanStatus"`
+	Comment          string   `json:"comment"`
+	RelatedDeviceIDs []string `json:"relatedDeviceIds"`
+}
+
+type UpdateDeviceRequest = CreateDeviceRequest
+
+var errDeviceNotFound = errors.New("device does not exist")
+
+func (s *Server) handleDevices(w http.ResponseWriter, r *http.Request) {
+	switch r.Method {
+	case http.MethodGet:
+		s.handleListDevices(w, r)
+	case http.MethodPost:
+		s.handleCreateDevice(w, r)
+	default:
+		writeError(w, http.StatusMethodNotAllowed, "Method not allowed")
+	}
+}
+
+func (s *Server) handleListDevices(w http.ResponseWriter, r *http.Request) {
+	rows, err := s.db.Query(
+		r.Context(),
+		`
+		SELECT
+			id,
+			inventory_number,
+			manufacturer,
+			model,
+			serial_number,
+			mac_address,
+			location,
+			loan_status,
+			comment,
+			created_at,
+			updated_at
+		FROM devices
+		ORDER BY inventory_number ASC
+		`,
+	)
+
+	if err != nil {
+		writeError(w, http.StatusInternalServerError, "Could not load devices")
+		return
+	}
+	defer rows.Close()
+
+	devices := make([]Device, 0)
+	deviceMap := map[string]*Device{}
+
+	for rows.Next() {
+		var device Device
+
+		if err := rows.Scan(
+			&device.ID,
+			&device.InventoryNumber,
+			&device.Manufacturer,
+			&device.Model,
+			&device.SerialNumber,
+			&device.MacAddress,
+			&device.Location,
+			&device.LoanStatus,
+			&device.Comment,
+			&device.CreatedAt,
+			&device.UpdatedAt,
+		); err != nil {
+			writeError(w, http.StatusInternalServerError, "Could not read devices")
+			return
+		}
+
+		device.RelatedDevices = []DeviceShort{}
+
+		devices = append(devices, device)
+		deviceMap[device.ID] = &devices[len(devices)-1]
+	}
+
+	if err := rows.Err(); err != nil {
+		writeError(w, http.StatusInternalServerError, "Could not read devices")
+		return
+	}
+
+	relationRows, err := s.db.Query(
+		r.Context(),
+		`
+		SELECT
+			device_relations.device_id,
+			related_devices.id,
+			related_devices.inventory_number,
+			related_devices.manufacturer,
+			related_devices.model
+		FROM device_relations
+		INNER JOIN devices AS related_devices
+			ON related_devices.id = device_relations.related_device_id
+		ORDER BY related_devices.inventory_number ASC
+		`,
+	)
+
+	if err != nil {
+		writeError(w, http.StatusInternalServerError, "Could not load device relations")
+		return
+	}
+	defer relationRows.Close()
+
+	for relationRows.Next() {
+		var deviceID string
+		var relatedDevice DeviceShort
+
+		if err := relationRows.Scan(
+			&deviceID,
+			&relatedDevice.ID,
+			&relatedDevice.InventoryNumber,
+			&relatedDevice.Manufacturer,
+			&relatedDevice.Model,
+		); err != nil {
+			writeError(w, http.StatusInternalServerError, "Could not read device relations")
+			return
+		}
+
+		device, exists := deviceMap[deviceID]
+		if exists {
+			device.RelatedDevices = append(device.RelatedDevices, relatedDevice)
+		}
+	}
+
+	if err := relationRows.Err(); err != nil {
+		writeError(w, http.StatusInternalServerError, "Could not read device relations")
+		return
+	}
+
+	writeJSON(w, http.StatusOK, map[string]any{
+		"devices": devices,
+	})
+}
+
+func (s *Server) handleCreateDevice(w http.ResponseWriter, r *http.Request) {
+	var input CreateDeviceRequest
+
+	if err := readJSON(r, &input); err != nil {
+		writeError(w, http.StatusBadRequest, "Invalid JSON")
+		return
+	}
+
+	normalizeDeviceInput(&input)
+
+	if input.InventoryNumber == "" {
+		writeError(w, http.StatusBadRequest, "Inventur-Nr. ist erforderlich")
+		return
+	}
+
+	user, ok := userFromContext(r.Context())
+	if !ok {
+		writeError(w, http.StatusUnauthorized, "Unauthorized")
+		return
+	}
+
+	tx, err := s.db.Begin(r.Context())
+	if err != nil {
+		writeError(w, http.StatusInternalServerError, "Could not create device")
+		return
+	}
+	defer tx.Rollback(r.Context())
+
+	var device Device
+
+	err = tx.QueryRow(
+		r.Context(),
+		`
+		INSERT INTO devices (
+			inventory_number,
+			manufacturer,
+			model,
+			serial_number,
+			mac_address,
+			location,
+			loan_status,
+			comment
+		)
+		VALUES ($1, $2, $3, $4, $5, $6, $7, $8)
+		RETURNING
+			id,
+			inventory_number,
+			manufacturer,
+			model,
+			serial_number,
+			mac_address,
+			location,
+			loan_status,
+			comment,
+			created_at,
+			updated_at
+		`,
+		input.InventoryNumber,
+		input.Manufacturer,
+		input.Model,
+		input.SerialNumber,
+		input.MacAddress,
+		input.Location,
+		input.LoanStatus,
+		input.Comment,
+	).Scan(
+		&device.ID,
+		&device.InventoryNumber,
+		&device.Manufacturer,
+		&device.Model,
+		&device.SerialNumber,
+		&device.MacAddress,
+		&device.Location,
+		&device.LoanStatus,
+		&device.Comment,
+		&device.CreatedAt,
+		&device.UpdatedAt,
+	)
+
+	if err != nil {
+		var pgErr *pgconn.PgError
+
+		if errors.As(err, &pgErr) && pgErr.Code == "23505" {
+			writeError(w, http.StatusConflict, "Gerät mit dieser Inventur-Nr., Seriennummer oder MAC-Adresse existiert bereits")
+			return
+		}
+
+		writeError(w, http.StatusInternalServerError, "Could not create device")
+		return
+	}
+
+	if err := syncDeviceRelations(r.Context(), tx, device.ID, input.RelatedDeviceIDs); err != nil {
+		if errors.Is(err, errDeviceNotFound) {
+			writeError(w, http.StatusBadRequest, "Zugeordnetes Gerät wurde nicht gefunden")
+			return
+		}
+
+		writeError(w, http.StatusInternalServerError, "Could not assign related device")
+		return
+	}
+
+	changes, err := buildDeviceCreateHistoryChanges(r.Context(), tx, input)
+	if err != nil {
+		writeError(w, http.StatusInternalServerError, "Could not create device history")
+		return
+	}
+
+	if err := recordDeviceHistory(r.Context(), tx, device.ID, user, "created", changes); err != nil {
+		writeError(w, http.StatusInternalServerError, "Could not create device history")
+		return
+	}
+
+	if err := tx.Commit(r.Context()); err != nil {
+		writeError(w, http.StatusInternalServerError, "Could not create device")
+		return
+	}
+
+	device.RelatedDevices = []DeviceShort{}
+
+	writeJSON(w, http.StatusCreated, map[string]any{
+		"device": device,
+	})
+}
+
+func (s *Server) handleUpdateDevice(w http.ResponseWriter, r *http.Request) {
+	deviceID := strings.TrimSpace(r.PathValue("id"))
+
+	if deviceID == "" {
+		writeError(w, http.StatusBadRequest, "Geräte-ID fehlt")
+		return
+	}
+
+	var input UpdateDeviceRequest
+
+	if err := readJSON(r, &input); err != nil {
+		writeError(w, http.StatusBadRequest, "Invalid JSON")
+		return
+	}
+
+	normalizeDeviceInput(&input)
+
+	if input.InventoryNumber == "" {
+		writeError(w, http.StatusBadRequest, "Inventur-Nr. ist erforderlich")
+		return
+	}
+
+	user, ok := userFromContext(r.Context())
+	if !ok {
+		writeError(w, http.StatusUnauthorized, "Unauthorized")
+		return
+	}
+
+	tx, err := s.db.Begin(r.Context())
+	if err != nil {
+		writeError(w, http.StatusInternalServerError, "Could not update device")
+		return
+	}
+	defer tx.Rollback(r.Context())
+
+	oldDevice, oldRelatedDeviceIDs, err := getDeviceForHistory(r.Context(), tx, deviceID)
+	if errors.Is(err, pgx.ErrNoRows) {
+		writeError(w, http.StatusNotFound, "Gerät wurde nicht gefunden")
+		return
+	}
+
+	if err != nil {
+		writeError(w, http.StatusInternalServerError, "Could not load device history state")
+		return
+	}
+
+	var device Device
+
+	err = tx.QueryRow(
+		r.Context(),
+		`
+		UPDATE devices
+		SET
+			inventory_number = $2,
+			manufacturer = $3,
+			model = $4,
+			serial_number = $5,
+			mac_address = $6,
+			location = $7,
+			loan_status = $8,
+			comment = $9,
+			updated_at = now()
+		WHERE id = $1
+		RETURNING
+			id,
+			inventory_number,
+			manufacturer,
+			model,
+			serial_number,
+			mac_address,
+			location,
+			loan_status,
+			comment,
+			created_at,
+			updated_at
+		`,
+		deviceID,
+		input.InventoryNumber,
+		input.Manufacturer,
+		input.Model,
+		input.SerialNumber,
+		input.MacAddress,
+		input.Location,
+		input.LoanStatus,
+		input.Comment,
+	).Scan(
+		&device.ID,
+		&device.InventoryNumber,
+		&device.Manufacturer,
+		&device.Model,
+		&device.SerialNumber,
+		&device.MacAddress,
+		&device.Location,
+		&device.LoanStatus,
+		&device.Comment,
+		&device.CreatedAt,
+		&device.UpdatedAt,
+	)
+
+	if errors.Is(err, pgx.ErrNoRows) {
+		writeError(w, http.StatusNotFound, "Gerät wurde nicht gefunden")
+		return
+	}
+
+	if err != nil {
+		var pgErr *pgconn.PgError
+
+		if errors.As(err, &pgErr) && pgErr.Code == "23505" {
+			writeError(w, http.StatusConflict, "Gerät mit dieser Inventur-Nr., Seriennummer oder MAC-Adresse existiert bereits")
+			return
+		}
+
+		writeError(w, http.StatusInternalServerError, "Could not update device")
+		return
+	}
+
+	if err := syncDeviceRelations(r.Context(), tx, device.ID, input.RelatedDeviceIDs); err != nil {
+		if errors.Is(err, errDeviceNotFound) {
+			writeError(w, http.StatusBadRequest, "Zugeordnetes Gerät wurde nicht gefunden")
+			return
+		}
+
+		writeError(w, http.StatusInternalServerError, "Could not update device relations")
+		return
+	}
+
+	changes, err := buildDeviceUpdateHistoryChanges(r.Context(), tx, oldDevice, oldRelatedDeviceIDs, input)
+	if err != nil {
+		writeError(w, http.StatusInternalServerError, "Could not create device history")
+		return
+	}
+
+	if len(changes) > 0 {
+		if err := recordDeviceHistory(r.Context(), tx, device.ID, user, "updated", changes); err != nil {
+			writeError(w, http.StatusInternalServerError, "Could not create device history")
+			return
+		}
+	}
+
+	if err := tx.Commit(r.Context()); err != nil {
+		writeError(w, http.StatusInternalServerError, "Could not update device")
+		return
+	}
+
+	device.RelatedDevices = []DeviceShort{}
+
+	writeJSON(w, http.StatusOK, map[string]any{
+		"device": device,
+	})
+}
+
+func ensureDeviceExists(ctx context.Context, tx pgx.Tx, deviceID string) error {
+	var exists bool
+
+	err := tx.QueryRow(
+		ctx,
+		`
+		SELECT EXISTS(
+			SELECT 1
+			FROM devices
+			WHERE id = $1
+		)
+		`,
+		deviceID,
+	).Scan(&exists)
+
+	if err != nil {
+		return err
+	}
+
+	if !exists {
+		return errDeviceNotFound
+	}
+
+	return nil
+}
+
+func normalizeDeviceInput(input *CreateDeviceRequest) {
+	input.InventoryNumber = strings.TrimSpace(input.InventoryNumber)
+	input.Manufacturer = strings.TrimSpace(input.Manufacturer)
+	input.Model = strings.TrimSpace(input.Model)
+	input.SerialNumber = strings.TrimSpace(input.SerialNumber)
+	input.MacAddress = strings.TrimSpace(input.MacAddress)
+	input.Location = strings.TrimSpace(input.Location)
+	input.LoanStatus = strings.TrimSpace(input.LoanStatus)
+	input.Comment = strings.TrimSpace(input.Comment)
+
+	if input.LoanStatus == "" {
+		input.LoanStatus = "Verfügbar"
+	}
+}
+
+func syncDeviceRelations(ctx context.Context, tx pgx.Tx, deviceID string, relatedDeviceIDs []string) error {
+	_, err := tx.Exec(
+		ctx,
+		`
+		DELETE FROM device_relations
+		WHERE device_id = $1 OR related_device_id = $1
+		`,
+		deviceID,
+	)
+
+	if err != nil {
+		return err
+	}
+
+	seen := map[string]bool{}
+
+	for _, relatedDeviceID := range relatedDeviceIDs {
+		relatedDeviceID = strings.TrimSpace(relatedDeviceID)
+
+		if relatedDeviceID == "" || relatedDeviceID == deviceID {
+			continue
+		}
+
+		if seen[relatedDeviceID] {
+			continue
+		}
+
+		seen[relatedDeviceID] = true
+
+		if err := ensureDeviceExists(ctx, tx, relatedDeviceID); err != nil {
+			return err
+		}
+
+		if err := assignRelatedDevice(ctx, tx, deviceID, relatedDeviceID); err != nil {
+			return err
+		}
+
+		if err := assignRelatedDevice(ctx, tx, relatedDeviceID, deviceID); err != nil {
+			return err
+		}
+	}
+
+	return nil
+}
+
+func assignRelatedDevice(ctx context.Context, tx pgx.Tx, deviceID string, relatedDeviceID string) error {
+	_, err := tx.Exec(
+		ctx,
+		`
+		INSERT INTO device_relations (
+			device_id,
+			related_device_id
+		)
+		VALUES ($1, $2)
+		ON CONFLICT (device_id, related_device_id) DO NOTHING
+		`,
+		deviceID,
+		relatedDeviceID,
+	)
+
+	return err
+}
+
+type deviceTransaction interface {
+	QueryRow(ctx context.Context, sql string, args ...any) pgx.Row
+	Exec(ctx context.Context, sql string, args ...any) (pgconn.CommandTag, error)
+}

backend/go.mod

@@ -0,0 +1,25 @@
+module main
+
+go 1.26.2
+
+require (
+	github.com/golang-jwt/jwt/v5 v5.3.1
+	github.com/jackc/pgx/v5 v5.9.2
+	golang.org/x/crypto v0.51.0
+)
+
+require (
+	github.com/jackc/chunkreader/v2 v2.0.1 // indirect
+	github.com/jackc/pgio v1.0.0 // indirect
+	github.com/jackc/pgproto3/v2 v2.3.3 // indirect
+)
+
+require (
+	github.com/jackc/pgconn v1.14.3
+	github.com/jackc/pgpassfile v1.0.0 // indirect
+	github.com/jackc/pgservicefile v0.0.0-20240606120523-5a60cdf6a761 // indirect
+	github.com/jackc/puddle/v2 v2.2.2 // indirect
+	github.com/joho/godotenv v1.5.1
+	golang.org/x/sync v0.20.0 // indirect
+	golang.org/x/text v0.37.0 // indirect
+)

backend/go.sum

@@ -0,0 +1,43 @@
+github.com/davecgh/go-spew v1.1.0/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
+github.com/davecgh/go-spew v1.1.1 h1:vj9j/u1bqnvCEfJOwUhtlOARqs3+rkHYY13jYWTU97c=
+github.com/davecgh/go-spew v1.1.1/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
+github.com/golang-jwt/jwt/v5 v5.3.1 h1:kYf81DTWFe7t+1VvL7eS+jKFVWaUnK9cB1qbwn63YCY=
+github.com/golang-jwt/jwt/v5 v5.3.1/go.mod h1:fxCRLWMO43lRc8nhHWY6LGqRcf+1gQWArsqaEUEa5bE=
+github.com/jackc/chunkreader/v2 v2.0.0/go.mod h1:odVSm741yZoC3dpHEUXIqA9tQRhFrgOHwnPIn9lDKlk=
+github.com/jackc/chunkreader/v2 v2.0.1 h1:i+RDz65UE+mmpjTfyz0MoVTnzeYxroil2G82ki7MGG8=
+github.com/jackc/chunkreader/v2 v2.0.1/go.mod h1:odVSm741yZoC3dpHEUXIqA9tQRhFrgOHwnPIn9lDKlk=
+github.com/jackc/pgconn v1.14.3 h1:bVoTr12EGANZz66nZPkMInAV/KHD2TxH9npjXXgiB3w=
+github.com/jackc/pgconn v1.14.3/go.mod h1:RZbme4uasqzybK2RK5c65VsHxoyaml09lx3tXOcO/VM=
+github.com/jackc/pgio v1.0.0 h1:g12B9UwVnzGhueNavwioyEEpAmqMe1E/BN9ES+8ovkE=
+github.com/jackc/pgio v1.0.0/go.mod h1:oP+2QK2wFfUWgr+gxjoBH9KGBb31Eio69xUb0w5bYf8=
+github.com/jackc/pgpassfile v1.0.0 h1:/6Hmqy13Ss2zCq62VdNG8tM1wchn8zjSGOBJ6icpsIM=
+github.com/jackc/pgpassfile v1.0.0/go.mod h1:CEx0iS5ambNFdcRtxPj5JhEz+xB6uRky5eyVu/W2HEg=
+github.com/jackc/pgproto3/v2 v2.3.3 h1:1HLSx5H+tXR9pW3in3zaztoEwQYRC9SQaYUHjTSUOag=
+github.com/jackc/pgproto3/v2 v2.3.3/go.mod h1:WfJCnwN3HIg9Ish/j3sgWXnAfK8A9Y0bwXYU5xKaEdA=
+github.com/jackc/pgservicefile v0.0.0-20240606120523-5a60cdf6a761 h1:iCEnooe7UlwOQYpKFhBabPMi4aNAfoODPEFNiAnClxo=
+github.com/jackc/pgservicefile v0.0.0-20240606120523-5a60cdf6a761/go.mod h1:5TJZWKEWniPve33vlWYSoGYefn3gLQRzjfDlhSJ9ZKM=
+github.com/jackc/pgx/v5 v5.9.2 h1:3ZhOzMWnR4yJ+RW1XImIPsD1aNSz4T4fyP7zlQb56hw=
+github.com/jackc/pgx/v5 v5.9.2/go.mod h1:mal1tBGAFfLHvZzaYh77YS/eC6IX9OWbRV1QIIM0Jn4=
+github.com/jackc/puddle/v2 v2.2.2 h1:PR8nw+E/1w0GLuRFSmiioY6UooMp6KJv0/61nB7icHo=
+github.com/jackc/puddle/v2 v2.2.2/go.mod h1:vriiEXHvEE654aYKXXjOvZM39qJ0q+azkZFrfEOc3H4=
+github.com/joho/godotenv v1.5.1 h1:7eLL/+HRGLY0ldzfGMeQkb7vMd0as4CfYvUVzLqw0N0=
+github.com/joho/godotenv v1.5.1/go.mod h1:f4LDr5Voq0i2e/R5DDNOoa2zzDfwtkZa6DnEwAbqwq4=
+github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZbAQM=
+github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
+github.com/stretchr/objx v0.1.0/go.mod h1:HFkY916IF+rwdDfMAkV7OtwuqBVzrE8GR6GFx+wExME=
+github.com/stretchr/testify v1.3.0/go.mod h1:M5WIy9Dh21IEIfnGCwXGc5bZfKNJtfHm1UVUgZn+9EI=
+github.com/stretchr/testify v1.4.0/go.mod h1:j7eGeouHqKxXV5pUuKE4zz7dFj8WfuZ+81PSLYec5m4=
+github.com/stretchr/testify v1.7.0/go.mod h1:6Fq8oRcR53rry900zMqJjRRixrwX3KX962/h/Wwjteg=
+github.com/stretchr/testify v1.11.1 h1:7s2iGBzp5EwR7/aIZr8ao5+dra3wiQyKjjFuvgVKu7U=
+github.com/stretchr/testify v1.11.1/go.mod h1:wZwfW3scLgRK+23gO65QZefKpKQRnfz6sD981Nm4B6U=
+golang.org/x/crypto v0.51.0 h1:IBPXwPfKxY7cWQZ38ZCIRPI50YLeevDLlLnyC5wRGTI=
+golang.org/x/crypto v0.51.0/go.mod h1:8AdwkbraGNABw2kOX6YFPs3WM22XqI4EXEd8g+x7Oc8=
+golang.org/x/sync v0.20.0 h1:e0PTpb7pjO8GAtTs2dQ6jYa5BWYlMuX047Dco/pItO4=
+golang.org/x/sync v0.20.0/go.mod h1:9xrNwdLfx4jkKbNva9FpL6vEN7evnE43NNNJQ2LF3+0=
+golang.org/x/text v0.37.0 h1:Cqjiwd9eSg8e0QAkyCaQTNHFIIzWtidPahFWR83rTrc=
+golang.org/x/text v0.37.0/go.mod h1:a5sjxXGs9hsn/AJVwuElvCAo9v8QYLzvavO5z2PiM38=
+gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
+gopkg.in/yaml.v2 v2.2.2/go.mod h1:hI93XBmqTisBFMUTm0b8Fm+jr3Dg1NNxqwp+5A1VGuI=
+gopkg.in/yaml.v3 v3.0.0-20200313102051-9f266ea9e77c/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=
+gopkg.in/yaml.v3 v3.0.1 h1:fxVm/GzAzEWqLHuvctI91KS9hhNmmWOoWu0XTYJS7CA=
+gopkg.in/yaml.v3 v3.0.1/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=

backend/history.go

@@ -0,0 +1,377 @@
+package main
+
+import (
+	"context"
+	"encoding/json"
+	"errors"
+	"net/http"
+	"strings"
+	"time"
+
+	"github.com/jackc/pgx/v5"
+)
+
+type DeviceHistoryEntry struct {
+	ID              string                `json:"id"`
+	DeviceID        string                `json:"deviceId"`
+	UserID          string                `json:"userId"`
+	UserDisplayName string                `json:"userDisplayName"`
+	Action          string                `json:"action"`
+	Changes         []DeviceHistoryChange `json:"changes"`
+	CreatedAt       time.Time             `json:"createdAt"`
+}
+
+type DeviceHistoryChange struct {
+	Field    string `json:"field"`
+	Label    string `json:"label"`
+	OldValue string `json:"oldValue"`
+	NewValue string `json:"newValue"`
+}
+
+func (s *Server) handleListDeviceHistory(w http.ResponseWriter, r *http.Request) {
+	deviceID := strings.TrimSpace(r.PathValue("id"))
+
+	if deviceID == "" {
+		writeError(w, http.StatusBadRequest, "Geräte-ID fehlt")
+		return
+	}
+
+	rows, err := s.db.Query(
+		r.Context(),
+		`
+		SELECT
+			h.id,
+			h.device_id,
+			COALESCE(h.user_id::TEXT, ''),
+			COALESCE(NULLIF(u.display_name, ''), NULLIF(u.username, ''), u.email, 'Unbekannt'),
+			h.action,
+			h.changes,
+			h.created_at
+		FROM device_history h
+		LEFT JOIN users u ON u.id = h.user_id
+		WHERE h.device_id = $1
+		ORDER BY h.created_at DESC
+		`,
+		deviceID,
+	)
+
+	if err != nil {
+		writeError(w, http.StatusInternalServerError, "Could not load device history")
+		return
+	}
+	defer rows.Close()
+
+	history := []DeviceHistoryEntry{}
+
+	for rows.Next() {
+		var entry DeviceHistoryEntry
+		var changesRaw []byte
+
+		if err := rows.Scan(
+			&entry.ID,
+			&entry.DeviceID,
+			&entry.UserID,
+			&entry.UserDisplayName,
+			&entry.Action,
+			&changesRaw,
+			&entry.CreatedAt,
+		); err != nil {
+			writeError(w, http.StatusInternalServerError, "Could not read device history")
+			return
+		}
+
+		if len(changesRaw) > 0 {
+			if err := json.Unmarshal(changesRaw, &entry.Changes); err != nil {
+				writeError(w, http.StatusInternalServerError, "Could not parse device history")
+				return
+			}
+		}
+
+		history = append(history, entry)
+	}
+
+	if err := rows.Err(); err != nil {
+		writeError(w, http.StatusInternalServerError, "Could not read device history")
+		return
+	}
+
+	writeJSON(w, http.StatusOK, map[string]any{
+		"history": history,
+	})
+}
+
+func userFromContext(ctx context.Context) (User, bool) {
+	user, ok := ctx.Value(userContextKey).(User)
+	return user, ok
+}
+
+func recordDeviceHistory(
+	ctx context.Context,
+	tx pgx.Tx,
+	deviceID string,
+	user User,
+	action string,
+	changes []DeviceHistoryChange,
+) error {
+	changesJSON, err := json.Marshal(changes)
+	if err != nil {
+		return err
+	}
+
+	_, err = tx.Exec(
+		ctx,
+		`
+		INSERT INTO device_history (
+			device_id,
+			user_id,
+			action,
+			changes
+		)
+		VALUES ($1, $2, $3, $4::JSONB)
+		`,
+		deviceID,
+		user.ID,
+		action,
+		string(changesJSON),
+	)
+
+	return err
+}
+
+func getDeviceForHistory(ctx context.Context, tx pgx.Tx, deviceID string) (Device, []string, error) {
+	var device Device
+
+	err := tx.QueryRow(
+		ctx,
+		`
+		SELECT
+			id,
+			inventory_number,
+			manufacturer,
+			model,
+			serial_number,
+			mac_address,
+			location,
+			loan_status,
+			comment,
+			created_at,
+			updated_at
+		FROM devices
+		WHERE id = $1
+		LIMIT 1
+		`,
+		deviceID,
+	).Scan(
+		&device.ID,
+		&device.InventoryNumber,
+		&device.Manufacturer,
+		&device.Model,
+		&device.SerialNumber,
+		&device.MacAddress,
+		&device.Location,
+		&device.LoanStatus,
+		&device.Comment,
+		&device.CreatedAt,
+		&device.UpdatedAt,
+	)
+
+	if err != nil {
+		return device, nil, err
+	}
+
+	rows, err := tx.Query(
+		ctx,
+		`
+		SELECT related_device_id
+		FROM device_relations
+		WHERE device_id = $1
+		ORDER BY related_device_id ASC
+		`,
+		deviceID,
+	)
+
+	if err != nil {
+		return device, nil, err
+	}
+	defer rows.Close()
+
+	relatedDeviceIDs := []string{}
+
+	for rows.Next() {
+		var relatedDeviceID string
+
+		if err := rows.Scan(&relatedDeviceID); err != nil {
+			return device, nil, err
+		}
+
+		relatedDeviceIDs = append(relatedDeviceIDs, relatedDeviceID)
+	}
+
+	if err := rows.Err(); err != nil {
+		return device, nil, err
+	}
+
+	return device, relatedDeviceIDs, nil
+}
+
+func buildDeviceCreateHistoryChanges(
+	ctx context.Context,
+	tx pgx.Tx,
+	input CreateDeviceRequest,
+) ([]DeviceHistoryChange, error) {
+	changes := []DeviceHistoryChange{}
+
+	changes = appendHistoryChange(changes, "inventoryNumber", "Inventur-Nr.", "", input.InventoryNumber)
+	changes = appendHistoryChange(changes, "manufacturer", "Hersteller", "", input.Manufacturer)
+	changes = appendHistoryChange(changes, "model", "Modell", "", input.Model)
+	changes = appendHistoryChange(changes, "serialNumber", "Seriennummer", "", input.SerialNumber)
+	changes = appendHistoryChange(changes, "macAddress", "MAC-Adresse", "", input.MacAddress)
+	changes = appendHistoryChange(changes, "location", "Standort", "", input.Location)
+	changes = appendHistoryChange(changes, "loanStatus", "Verleih-Status", "", input.LoanStatus)
+	changes = appendHistoryChange(changes, "comment", "Kommentar", "", input.Comment)
+
+	relatedDevices, err := formatRelatedDeviceLabels(ctx, tx, input.RelatedDeviceIDs)
+	if err != nil {
+		return nil, err
+	}
+
+	changes = appendHistoryChange(changes, "relatedDeviceIds", "Zugeordnete Geräte / Zubehör", "", relatedDevices)
+
+	return changes, nil
+}
+
+func buildDeviceUpdateHistoryChanges(
+	ctx context.Context,
+	tx pgx.Tx,
+	oldDevice Device,
+	oldRelatedDeviceIDs []string,
+	input UpdateDeviceRequest,
+) ([]DeviceHistoryChange, error) {
+	changes := []DeviceHistoryChange{}
+
+	changes = appendHistoryChange(changes, "inventoryNumber", "Inventur-Nr.", oldDevice.InventoryNumber, input.InventoryNumber)
+	changes = appendHistoryChange(changes, "manufacturer", "Hersteller", oldDevice.Manufacturer, input.Manufacturer)
+	changes = appendHistoryChange(changes, "model", "Modell", oldDevice.Model, input.Model)
+	changes = appendHistoryChange(changes, "serialNumber", "Seriennummer", oldDevice.SerialNumber, input.SerialNumber)
+	changes = appendHistoryChange(changes, "macAddress", "MAC-Adresse", oldDevice.MacAddress, input.MacAddress)
+	changes = appendHistoryChange(changes, "location", "Standort", oldDevice.Location, input.Location)
+	changes = appendHistoryChange(changes, "loanStatus", "Verleih-Status", oldDevice.LoanStatus, input.LoanStatus)
+	changes = appendHistoryChange(changes, "comment", "Kommentar", oldDevice.Comment, input.Comment)
+
+	oldRelatedDevices, err := formatRelatedDeviceLabels(ctx, tx, oldRelatedDeviceIDs)
+	if err != nil {
+		return nil, err
+	}
+
+	newRelatedDevices, err := formatRelatedDeviceLabels(ctx, tx, input.RelatedDeviceIDs)
+	if err != nil {
+		return nil, err
+	}
+
+	changes = appendHistoryChange(
+		changes,
+		"relatedDeviceIds",
+		"Zugeordnete Geräte / Zubehör",
+		oldRelatedDevices,
+		newRelatedDevices,
+	)
+
+	return changes, nil
+}
+
+func appendHistoryChange(
+	changes []DeviceHistoryChange,
+	field string,
+	label string,
+	oldValue string,
+	newValue string,
+) []DeviceHistoryChange {
+	oldValue = strings.TrimSpace(oldValue)
+	newValue = strings.TrimSpace(newValue)
+
+	if oldValue == newValue {
+		return changes
+	}
+
+	return append(changes, DeviceHistoryChange{
+		Field:    field,
+		Label:    label,
+		OldValue: displayHistoryValue(oldValue),
+		NewValue: displayHistoryValue(newValue),
+	})
+}
+
+func displayHistoryValue(value string) string {
+	value = strings.TrimSpace(value)
+
+	if value == "" {
+		return "-"
+	}
+
+	return value
+}
+
+func formatRelatedDeviceLabels(ctx context.Context, tx pgx.Tx, deviceIDs []string) (string, error) {
+	normalizedDeviceIDs := normalizeDeviceIDs(deviceIDs)
+
+	if len(normalizedDeviceIDs) == 0 {
+		return "-", nil
+	}
+
+	labels := []string{}
+
+	for _, deviceID := range normalizedDeviceIDs {
+		var label string
+
+		err := tx.QueryRow(
+			ctx,
+			`
+			SELECT TRIM(CONCAT_WS(' ', inventory_number, NULLIF(manufacturer, ''), NULLIF(model, '')))
+			FROM devices
+			WHERE id = $1
+			LIMIT 1
+			`,
+			deviceID,
+		).Scan(&label)
+
+		if errors.Is(err, pgx.ErrNoRows) {
+			return "", errDeviceNotFound
+		}
+
+		if err != nil {
+			return "", err
+		}
+
+		label = strings.TrimSpace(label)
+
+		if label == "" {
+			label = deviceID
+		}
+
+		labels = append(labels, label)
+	}
+
+	return strings.Join(labels, ", "), nil
+}
+
+func normalizeDeviceIDs(deviceIDs []string) []string {
+	seen := map[string]bool{}
+	result := []string{}
+
+	for _, deviceID := range deviceIDs {
+		deviceID = strings.TrimSpace(deviceID)
+
+		if deviceID == "" {
+			continue
+		}
+
+		if seen[deviceID] {
+			continue
+		}
+
+		seen[deviceID] = true
+		result = append(result, deviceID)
+	}
+
+	return result
+}

backend/main.go

@@ -0,0 +1,76 @@
+// backend\main.go
+
+package main
+
+import (
+	"context"
+	"encoding/json"
+	"log"
+	"net/http"
+	"os"
+	"strings"
+
+	"github.com/jackc/pgx/v5/pgxpool"
+	"github.com/joho/godotenv"
+)
+
+func main() {
+	if err := godotenv.Load(); err != nil {
+		log.Println("Keine .env Datei gefunden, nutze System-Environment oder Fallbacks")
+	}
+
+	port := env("PORT", "8080")
+	databaseURL := env("DATABASE_URL", "postgres://postgres:postgres@localhost:5432/teg?sslmode=disable")
+	jwtSecret := env("JWT_SECRET", "dev-secret-change-me")
+	frontendOrigin := env("FRONTEND_ORIGIN", "http://localhost:5173")
+
+	ctx := context.Background()
+
+	db, err := pgxpool.New(ctx, databaseURL)
+	if err != nil {
+		log.Fatal(err)
+	}
+	defer db.Close()
+
+	if err := db.Ping(ctx); err != nil {
+		log.Fatal(err)
+	}
+
+	server := NewServer(db, jwtSecret, frontendOrigin)
+
+	log.Printf("Backend läuft auf http://localhost:%s", port)
+
+	if err := http.ListenAndServe(":"+port, server.Routes()); err != nil {
+		log.Fatal(err)
+	}
+}
+
+func readJSON(r *http.Request, target any) error {
+	return json.NewDecoder(r.Body).Decode(target)
+}
+
+func writeJSON(w http.ResponseWriter, status int, payload any) {
+	w.Header().Set("Content-Type", "application/json")
+	w.WriteHeader(status)
+	_ = json.NewEncoder(w).Encode(payload)
+}
+
+func writeError(w http.ResponseWriter, status int, message string) {
+	writeJSON(w, status, map[string]string{
+		"error": message,
+	})
+}
+
+func normalizeEmail(email string) string {
+	return strings.ToLower(strings.TrimSpace(email))
+}
+
+func env(key string, fallback string) string {
+	value := os.Getenv(key)
+
+	if value == "" {
+		return fallback
+	}
+
+	return value
+}

backend/routes.go

@@ -0,0 +1,23 @@
+// backend\routes.go
+
+package main
+
+import "net/http"
+
+func (s *Server) Routes() http.Handler {
+	mux := http.NewServeMux()
+
+	mux.HandleFunc("GET /health", s.handleHealth)
+
+	mux.HandleFunc("POST /auth/register", s.handleRegister)
+	mux.HandleFunc("POST /auth/login", s.handleLogin)
+	mux.HandleFunc("POST /auth/logout", s.handleLogout)
+	mux.HandleFunc("GET /auth/me", s.requireAuth(s.handleMe))
+
+	mux.HandleFunc("GET /devices", s.requireAuth(s.handleListDevices))
+	mux.HandleFunc("POST /devices", s.requireAuth(s.handleCreateDevice))
+	mux.HandleFunc("PUT /devices/{id}", s.requireAuth(s.handleUpdateDevice))
+	mux.HandleFunc("GET /devices/{id}/history", s.requireAuth(s.handleListDeviceHistory))
+
+	return s.cors(mux)
+}

backend/server.go

@@ -0,0 +1,461 @@
+// backend\server.go
+
+package main
+
+import (
+	"context"
+	"crypto/subtle"
+	"errors"
+	"net/http"
+	"strings"
+	"time"
+
+	"github.com/golang-jwt/jwt/v5"
+	"github.com/jackc/pgx/v5"
+	"github.com/jackc/pgx/v5/pgxpool"
+	"golang.org/x/crypto/bcrypt"
+)
+
+type contextKey string
+
+const userContextKey contextKey = "user"
+
+type Server struct {
+	db             *pgxpool.Pool
+	jwtSecret      []byte
+	frontendOrigin string
+}
+
+type User struct {
+	ID          string   `json:"id"`
+	Username    string   `json:"username"`
+	DisplayName string   `json:"displayName"`
+	Email       string   `json:"email"`
+	Avatar      string   `json:"avatar"`
+	Unit        string   `json:"unit"`
+	Group       string   `json:"group"`
+	Rights      []string `json:"rights"`
+	Teams       []Team   `json:"teams"`
+}
+
+type Team struct {
+	ID      string `json:"id"`
+	Name    string `json:"name"`
+	Initial string `json:"initial"`
+	Href    string `json:"href"`
+	Current bool   `json:"current"`
+}
+
+type RegisterRequest struct {
+	Username    string   `json:"username"`
+	DisplayName string   `json:"displayName"`
+	Email       string   `json:"email"`
+	Password    string   `json:"password"`
+	Avatar      string   `json:"avatar"`
+	Unit        string   `json:"unit"`
+	Group       string   `json:"group"`
+	Rights      []string `json:"rights"`
+}
+
+type LoginRequest struct {
+	Identifier string `json:"identifier"`
+	Password   string `json:"password"`
+}
+
+type Claims struct {
+	UserID string `json:"user_id"`
+	Email  string `json:"email"`
+	jwt.RegisteredClaims
+}
+
+func NewServer(db *pgxpool.Pool, jwtSecret string, frontendOrigin string) *Server {
+	return &Server{
+		db:             db,
+		jwtSecret:      []byte(jwtSecret),
+		frontendOrigin: frontendOrigin,
+	}
+}
+
+func (s *Server) handleHealth(w http.ResponseWriter, r *http.Request) {
+	writeJSON(w, http.StatusOK, map[string]string{
+		"status": "ok",
+	})
+}
+
+func (s *Server) handleRegister(w http.ResponseWriter, r *http.Request) {
+	var input RegisterRequest
+
+	if err := readJSON(r, &input); err != nil {
+		writeError(w, http.StatusBadRequest, "Invalid JSON")
+		return
+	}
+
+	username := normalizeUsername(input.Username)
+	email := normalizeEmail(input.Email)
+
+	if username == "" || email == "" || len(input.Password) < 8 {
+		writeError(w, http.StatusBadRequest, "Benutzername, E-Mail und Passwort mit mindestens 8 Zeichen sind erforderlich")
+		return
+	}
+
+	displayName := strings.TrimSpace(input.DisplayName)
+	if displayName == "" {
+		displayName = username
+	}
+
+	group := strings.TrimSpace(input.Group)
+	if group == "" {
+		group = "user"
+	}
+
+	rights := input.Rights
+	if len(rights) == 0 {
+		rights = []string{"user"}
+	}
+
+	passwordHash, err := bcrypt.GenerateFromPassword([]byte(input.Password), bcrypt.DefaultCost)
+	if err != nil {
+		writeError(w, http.StatusInternalServerError, "Could not hash password")
+		return
+	}
+
+	var user User
+
+	err = s.db.QueryRow(
+		r.Context(),
+		`
+		INSERT INTO users (
+			username,
+			display_name,
+			email,
+			password_hash,
+			avatar,
+			unit,
+			user_group,
+			rights
+		)
+		VALUES ($1, $2, $3, $4, $5, $6, $7, $8)
+		RETURNING
+			id,
+			COALESCE(username, ''),
+			COALESCE(display_name, ''),
+			email,
+			COALESCE(avatar, ''),
+			COALESCE(unit, ''),
+			COALESCE(user_group, ''),
+			COALESCE(rights, '{}'::TEXT[])
+		`,
+		username,
+		displayName,
+		email,
+		string(passwordHash),
+		strings.TrimSpace(input.Avatar),
+		strings.TrimSpace(input.Unit),
+		group,
+		rights,
+	).Scan(
+		&user.ID,
+		&user.Username,
+		&user.DisplayName,
+		&user.Email,
+		&user.Avatar,
+		&user.Unit,
+		&user.Group,
+		&user.Rights,
+	)
+
+	if err != nil {
+		writeError(w, http.StatusConflict, "User already exists")
+		return
+	}
+
+	if err := s.setSessionCookie(w, user); err != nil {
+		writeError(w, http.StatusInternalServerError, "Could not create session")
+		return
+	}
+
+	writeJSON(w, http.StatusCreated, map[string]any{
+		"user": user,
+	})
+}
+
+func (s *Server) handleLogin(w http.ResponseWriter, r *http.Request) {
+	var input LoginRequest
+
+	if err := readJSON(r, &input); err != nil {
+		writeError(w, http.StatusBadRequest, "Invalid JSON")
+		return
+	}
+
+	identifier := strings.ToLower(strings.TrimSpace(input.Identifier))
+
+	if identifier == "" || input.Password == "" {
+		writeError(w, http.StatusBadRequest, "Benutzername/E-Mail und Passwort sind erforderlich")
+		return
+	}
+
+	user, passwordHash, err := s.getUserByIdentifier(r.Context(), identifier)
+
+	if errors.Is(err, pgx.ErrNoRows) {
+		writeError(w, http.StatusUnauthorized, "Invalid username/email or password")
+		return
+	}
+
+	if err != nil {
+		writeError(w, http.StatusInternalServerError, "Login failed")
+		return
+	}
+
+	if err := bcrypt.CompareHashAndPassword([]byte(passwordHash), []byte(input.Password)); err != nil {
+		writeError(w, http.StatusUnauthorized, "Invalid username/email or password")
+		return
+	}
+
+	if err := s.setSessionCookie(w, user); err != nil {
+		writeError(w, http.StatusInternalServerError, "Could not create session")
+		return
+	}
+
+	writeJSON(w, http.StatusOK, map[string]any{
+		"user": user,
+	})
+}
+
+func (s *Server) handleLogout(w http.ResponseWriter, r *http.Request) {
+	http.SetCookie(w, &http.Cookie{
+		Name:     "session",
+		Value:    "",
+		Path:     "/",
+		MaxAge:   -1,
+		HttpOnly: true,
+		SameSite: http.SameSiteLaxMode,
+		Secure:   false,
+	})
+
+	writeJSON(w, http.StatusOK, map[string]string{
+		"message": "Logged out",
+	})
+}
+
+func (s *Server) handleMe(w http.ResponseWriter, r *http.Request) {
+	user, ok := r.Context().Value(userContextKey).(User)
+
+	if !ok {
+		writeError(w, http.StatusUnauthorized, "Unauthorized")
+		return
+	}
+
+	writeJSON(w, http.StatusOK, map[string]any{
+		"user": user,
+	})
+}
+
+func (s *Server) setSessionCookie(w http.ResponseWriter, user User) error {
+	now := time.Now()
+
+	claims := Claims{
+		UserID: user.ID,
+		Email:  user.Email,
+		RegisteredClaims: jwt.RegisteredClaims{
+			Subject:   user.ID,
+			IssuedAt:  jwt.NewNumericDate(now),
+			ExpiresAt: jwt.NewNumericDate(now.Add(24 * time.Hour)),
+		},
+	}
+
+	token := jwt.NewWithClaims(jwt.SigningMethodHS256, claims)
+
+	tokenString, err := token.SignedString(s.jwtSecret)
+	if err != nil {
+		return err
+	}
+
+	http.SetCookie(w, &http.Cookie{
+		Name:     "session",
+		Value:    tokenString,
+		Path:     "/",
+		MaxAge:   60 * 60 * 24,
+		HttpOnly: true,
+		SameSite: http.SameSiteLaxMode,
+
+		// In Produktion auf true setzen, wenn HTTPS aktiv ist.
+		Secure: false,
+	})
+
+	return nil
+}
+
+func (s *Server) requireAuth(next http.HandlerFunc) http.HandlerFunc {
+	return func(w http.ResponseWriter, r *http.Request) {
+		cookie, err := r.Cookie("session")
+		if err != nil {
+			writeError(w, http.StatusUnauthorized, "Unauthorized")
+			return
+		}
+
+		claims := &Claims{}
+
+		token, err := jwt.ParseWithClaims(cookie.Value, claims, func(token *jwt.Token) (any, error) {
+			if subtle.ConstantTimeCompare([]byte(token.Method.Alg()), []byte(jwt.SigningMethodHS256.Alg())) != 1 {
+				return nil, errors.New("unexpected signing method")
+			}
+
+			return s.jwtSecret, nil
+		})
+
+		if err != nil || !token.Valid {
+			writeError(w, http.StatusUnauthorized, "Unauthorized")
+			return
+		}
+
+		user, err := s.getUserByID(r.Context(), claims.UserID)
+		if err != nil {
+			writeError(w, http.StatusUnauthorized, "Unauthorized")
+			return
+		}
+
+		ctx := context.WithValue(r.Context(), userContextKey, user)
+
+		next(w, r.WithContext(ctx))
+	}
+}
+
+func (s *Server) getUserByIdentifier(ctx context.Context, identifier string) (User, string, error) {
+	var user User
+	var passwordHash string
+
+	err := s.db.QueryRow(
+		ctx,
+		`
+		SELECT
+			id,
+			COALESCE(username, ''),
+			COALESCE(display_name, ''),
+			email,
+			password_hash,
+			COALESCE(avatar, ''),
+			COALESCE(unit, ''),
+			COALESCE(user_group, ''),
+			COALESCE(rights, '{}'::TEXT[])
+		FROM users
+		WHERE lower(email) = $1 OR lower(username) = $1
+		LIMIT 1
+		`,
+		identifier,
+	).Scan(
+		&user.ID,
+		&user.Username,
+		&user.DisplayName,
+		&user.Email,
+		&passwordHash,
+		&user.Avatar,
+		&user.Unit,
+		&user.Group,
+		&user.Rights,
+	)
+
+	if err != nil {
+		return user, passwordHash, err
+	}
+
+	teams, err := s.getTeamsForUser(ctx, user.ID)
+	if err != nil {
+		return user, passwordHash, err
+	}
+
+	user.Teams = teams
+
+	return user, passwordHash, nil
+}
+
+func (s *Server) getUserByID(ctx context.Context, userID string) (User, error) {
+	var user User
+
+	err := s.db.QueryRow(
+		ctx,
+		`
+		SELECT
+			id,
+			COALESCE(username, ''),
+			COALESCE(display_name, ''),
+			email,
+			COALESCE(avatar, ''),
+			COALESCE(unit, ''),
+			COALESCE(user_group, ''),
+			COALESCE(rights, '{}'::TEXT[])
+		FROM users
+		WHERE id = $1
+		LIMIT 1
+		`,
+		userID,
+	).Scan(
+		&user.ID,
+		&user.Username,
+		&user.DisplayName,
+		&user.Email,
+		&user.Avatar,
+		&user.Unit,
+		&user.Group,
+		&user.Rights,
+	)
+
+	if err != nil {
+		return user, err
+	}
+
+	teams, err := s.getTeamsForUser(ctx, user.ID)
+	if err != nil {
+		return user, err
+	}
+
+	user.Teams = teams
+
+	return user, nil
+}
+
+func normalizeUsername(username string) string {
+	return strings.ToLower(strings.TrimSpace(username))
+}
+
+func (s *Server) getTeamsForUser(ctx context.Context, userID string) ([]Team, error) {
+	rows, err := s.db.Query(
+		ctx,
+		`
+		SELECT
+			t.id,
+			t.name,
+			t.initial,
+			t.href
+		FROM teams t
+		INNER JOIN user_teams ut ON ut.team_id = t.id
+		WHERE ut.user_id = $1
+		ORDER BY t.name ASC
+		`,
+		userID,
+	)
+
+	if err != nil {
+		return nil, err
+	}
+
+	defer rows.Close()
+
+	teams := []Team{}
+
+	for rows.Next() {
+		var team Team
+
+		if err := rows.Scan(&team.ID, &team.Name, &team.Initial, &team.Href); err != nil {
+			return nil, err
+		}
+
+		team.Current = false
+		teams = append(teams, team)
+	}
+
+	if err := rows.Err(); err != nil {
+		return nil, err
+	}
+
+	return teams, nil
+}

backend/setup/main.go

@@ -0,0 +1,550 @@
+// backend\setup\main.go
+
+package main
+
+import (
+	"context"
+	"crypto/rand"
+	"encoding/base64"
+	"errors"
+	"flag"
+	"fmt"
+	"log"
+	"net/url"
+	"os"
+	"strings"
+	"time"
+
+	"github.com/jackc/pgx/v5"
+	"github.com/jackc/pgx/v5/pgxpool"
+	"github.com/joho/godotenv"
+	"golang.org/x/crypto/bcrypt"
+)
+
+func main() {
+	reset := flag.Bool("reset", false, "Datenbank komplett löschen und neu anlegen")
+	flag.Parse()
+
+	if err := godotenv.Load(".env", "backend/.env"); err != nil {
+		log.Println("Keine .env Datei gefunden, nutze System-Environment oder Fallbacks")
+	}
+
+	databaseURL := env("DATABASE_URL", "postgres://postgres:postgres@localhost:5432/teg?sslmode=disable")
+
+	parsedURL, err := url.Parse(databaseURL)
+	if err != nil {
+		log.Fatal(err)
+	}
+
+	databaseName := strings.TrimPrefix(parsedURL.Path, "/")
+	if databaseName == "" {
+		log.Fatal("DATABASE_URL enthält keinen Datenbanknamen")
+	}
+
+	ctx, cancel := context.WithTimeout(context.Background(), 30*time.Second)
+	defer cancel()
+
+	if *reset {
+		if err := dropDatabaseIfExists(ctx, parsedURL, databaseName); err != nil {
+			log.Fatal(err)
+		}
+	}
+
+	if err := createDatabaseIfNotExists(ctx, parsedURL, databaseName); err != nil {
+		log.Fatal(err)
+	}
+
+	db, err := pgxpool.New(ctx, databaseURL)
+	if err != nil {
+		log.Fatal(err)
+	}
+	defer db.Close()
+
+	if err := db.Ping(ctx); err != nil {
+		log.Fatal(err)
+	}
+
+	if err := createSchema(ctx, db); err != nil {
+		log.Fatal(err)
+	}
+
+	password, created, err := createAdminIfNotExists(ctx, db)
+	if err != nil {
+		log.Fatal(err)
+	}
+
+	printAdminResult(password, created)
+}
+
+func dropDatabaseIfExists(ctx context.Context, parsedURL *url.URL, databaseName string) error {
+	if databaseName == "postgres" || databaseName == "template0" || databaseName == "template1" {
+		return fmt.Errorf("datenbank %q darf nicht per -reset gelöscht werden", databaseName)
+	}
+
+	maintenanceURL := *parsedURL
+	maintenanceURL.Path = "/postgres"
+
+	db, err := pgxpool.New(ctx, maintenanceURL.String())
+	if err != nil {
+		return err
+	}
+	defer db.Close()
+
+	var exists bool
+
+	err = db.QueryRow(
+		ctx,
+		`SELECT EXISTS(SELECT 1 FROM pg_database WHERE datname = $1)`,
+		databaseName,
+	).Scan(&exists)
+
+	if err != nil {
+		return err
+	}
+
+	if !exists {
+		fmt.Printf("Datenbank %q existiert nicht, Reset übersprungen\n", databaseName)
+		return nil
+	}
+
+	fmt.Printf("Datenbank %q wird zurückgesetzt...\n", databaseName)
+
+	_, err = db.Exec(
+		ctx,
+		`
+		SELECT pg_terminate_backend(pid)
+		FROM pg_stat_activity
+		WHERE datname = $1
+		  AND pid <> pg_backend_pid()
+		`,
+		databaseName,
+	)
+
+	if err != nil {
+		return err
+	}
+
+	_, err = db.Exec(ctx, `DROP DATABASE IF EXISTS `+quoteIdentifier(databaseName))
+	if err != nil {
+		return err
+	}
+
+	fmt.Printf("Datenbank %q wurde gelöscht\n", databaseName)
+
+	return nil
+}
+
+func createDatabaseIfNotExists(ctx context.Context, parsedURL *url.URL, databaseName string) error {
+	maintenanceURL := *parsedURL
+	maintenanceURL.Path = "/postgres"
+
+	db, err := pgxpool.New(ctx, maintenanceURL.String())
+	if err != nil {
+		return err
+	}
+	defer db.Close()
+
+	var exists bool
+
+	err = db.QueryRow(
+		ctx,
+		`SELECT EXISTS(SELECT 1 FROM pg_database WHERE datname = $1)`,
+		databaseName,
+	).Scan(&exists)
+
+	if err != nil {
+		return err
+	}
+
+	if exists {
+		fmt.Printf("Datenbank %q existiert bereits\n", databaseName)
+		return nil
+	}
+
+	_, err = db.Exec(ctx, `CREATE DATABASE `+quoteIdentifier(databaseName))
+	if err != nil {
+		return err
+	}
+
+	fmt.Printf("Datenbank %q wurde erstellt\n", databaseName)
+
+	return nil
+}
+
+func createSchema(ctx context.Context, db *pgxpool.Pool) error {
+	queries := []string{
+		`CREATE EXTENSION IF NOT EXISTS pgcrypto`,
+
+		`
+		CREATE TABLE IF NOT EXISTS users (
+			id UUID PRIMARY KEY DEFAULT gen_random_uuid(),
+
+			username TEXT UNIQUE,
+			display_name TEXT,
+
+			email TEXT NOT NULL UNIQUE,
+			password_hash TEXT NOT NULL,
+
+			avatar TEXT,
+			unit TEXT,
+			user_group TEXT,
+			rights TEXT[] NOT NULL DEFAULT '{}'::TEXT[],
+
+			created_at TIMESTAMPTZ NOT NULL DEFAULT now(),
+			updated_at TIMESTAMPTZ NOT NULL DEFAULT now()
+		)
+		`,
+
+		`
+		CREATE TABLE IF NOT EXISTS teams (
+			id UUID PRIMARY KEY DEFAULT gen_random_uuid(),
+
+			name TEXT NOT NULL UNIQUE,
+			initial TEXT NOT NULL,
+			href TEXT NOT NULL DEFAULT '#',
+
+			created_at TIMESTAMPTZ NOT NULL DEFAULT now(),
+			updated_at TIMESTAMPTZ NOT NULL DEFAULT now()
+		)
+		`,
+
+		`
+		CREATE TABLE IF NOT EXISTS user_teams (
+			user_id UUID NOT NULL REFERENCES users(id) ON DELETE CASCADE,
+			team_id UUID NOT NULL REFERENCES teams(id) ON DELETE CASCADE,
+
+			created_at TIMESTAMPTZ NOT NULL DEFAULT now(),
+
+			PRIMARY KEY (user_id, team_id)
+		)
+		`,
+
+		`
+		CREATE TABLE IF NOT EXISTS devices (
+			id UUID PRIMARY KEY DEFAULT gen_random_uuid(),
+
+			inventory_number TEXT NOT NULL,
+			manufacturer TEXT NOT NULL DEFAULT '',
+			model TEXT NOT NULL DEFAULT '',
+			serial_number TEXT NOT NULL DEFAULT '',
+			mac_address TEXT NOT NULL DEFAULT '',
+			location TEXT NOT NULL DEFAULT '',
+			loan_status TEXT NOT NULL DEFAULT 'Verfügbar',
+			comment TEXT NOT NULL DEFAULT '',
+
+			created_at TIMESTAMPTZ NOT NULL DEFAULT now(),
+			updated_at TIMESTAMPTZ NOT NULL DEFAULT now()
+		)
+		`,
+
+		`
+		CREATE TABLE IF NOT EXISTS device_relations (
+			device_id UUID NOT NULL REFERENCES devices(id) ON DELETE CASCADE,
+			related_device_id UUID NOT NULL REFERENCES devices(id) ON DELETE CASCADE,
+
+			created_at TIMESTAMPTZ NOT NULL DEFAULT now(),
+
+			PRIMARY KEY (device_id, related_device_id),
+			CONSTRAINT device_relations_no_self_reference CHECK (device_id <> related_device_id)
+		)
+		`,
+
+		`
+		CREATE TABLE IF NOT EXISTS device_history (
+			id UUID PRIMARY KEY DEFAULT gen_random_uuid(),
+
+			device_id UUID NOT NULL REFERENCES devices(id) ON DELETE CASCADE,
+			user_id UUID REFERENCES users(id) ON DELETE SET NULL,
+
+			action TEXT NOT NULL,
+			changes JSONB NOT NULL DEFAULT '[]'::JSONB,
+
+			created_at TIMESTAMPTZ NOT NULL DEFAULT now()
+		)
+		`,
+
+		`CREATE INDEX IF NOT EXISTS idx_users_email ON users(email)`,
+		`CREATE INDEX IF NOT EXISTS idx_users_username ON users(username)`,
+
+		`CREATE INDEX IF NOT EXISTS idx_teams_name ON teams(name)`,
+		`CREATE INDEX IF NOT EXISTS idx_user_teams_user_id ON user_teams(user_id)`,
+		`CREATE INDEX IF NOT EXISTS idx_user_teams_team_id ON user_teams(team_id)`,
+
+		`CREATE UNIQUE INDEX IF NOT EXISTS idx_devices_inventory_number_unique ON devices(lower(inventory_number))`,
+		`CREATE UNIQUE INDEX IF NOT EXISTS idx_devices_serial_number_unique ON devices(lower(serial_number)) WHERE serial_number <> ''`,
+		`CREATE UNIQUE INDEX IF NOT EXISTS idx_devices_mac_address_unique ON devices(lower(mac_address)) WHERE mac_address <> ''`,
+
+		`CREATE INDEX IF NOT EXISTS idx_devices_manufacturer ON devices(manufacturer)`,
+		`CREATE INDEX IF NOT EXISTS idx_devices_model ON devices(model)`,
+		`CREATE INDEX IF NOT EXISTS idx_devices_location ON devices(location)`,
+		`CREATE INDEX IF NOT EXISTS idx_devices_loan_status ON devices(loan_status)`,
+
+		`CREATE INDEX IF NOT EXISTS idx_device_relations_device_id ON device_relations(device_id)`,
+		`CREATE INDEX IF NOT EXISTS idx_device_relations_related_device_id ON device_relations(related_device_id)`,
+
+		`CREATE INDEX IF NOT EXISTS idx_device_history_device_id ON device_history(device_id)`,
+		`CREATE INDEX IF NOT EXISTS idx_device_history_user_id ON device_history(user_id)`,
+		`CREATE INDEX IF NOT EXISTS idx_device_history_created_at ON device_history(created_at)`,
+	}
+
+	for _, query := range queries {
+		if _, err := db.Exec(ctx, query); err != nil {
+			return err
+		}
+	}
+
+	fmt.Println("Tabellen und Indizes wurden erstellt oder existieren bereits")
+
+	return nil
+}
+
+func createAdminIfNotExists(ctx context.Context, db *pgxpool.Pool) (string, bool, error) {
+	adminUsername := env("ADMIN_USERNAME", "admin")
+	adminDisplayName := env("ADMIN_DISPLAY_NAME", "Administrator")
+	adminEmail := env("ADMIN_EMAIL", "admin@example.com")
+	adminAvatar := env("ADMIN_AVATAR", "")
+	adminUnit := env("ADMIN_UNIT", "Administration")
+	adminGroup := env("ADMIN_GROUP", "admin")
+	adminRights := splitCSV(env("ADMIN_RIGHTS", "admin,users:read,users:write,teams:read,teams:write,devices:read,devices:write"))
+
+	adminTeamName := env("ADMIN_TEAM_NAME", "Administration")
+	adminTeamInitial := env("ADMIN_TEAM_INITIAL", "A")
+	adminTeamHref := env("ADMIN_TEAM_HREF", "#")
+
+	teamID, err := ensureTeam(ctx, db, adminTeamName, adminTeamInitial, adminTeamHref)
+	if err != nil {
+		return "", false, err
+	}
+
+	var existingUserID string
+
+	err = db.QueryRow(
+		ctx,
+		`
+		SELECT id
+		FROM users
+		WHERE username = $1 OR email = $2
+		LIMIT 1
+		`,
+		adminUsername,
+		adminEmail,
+	).Scan(&existingUserID)
+
+	if err == nil {
+		if err := assignUserToTeam(ctx, db, existingUserID, teamID); err != nil {
+			return "", false, err
+		}
+
+		return "", false, nil
+	}
+
+	if !errors.Is(err, pgx.ErrNoRows) {
+		return "", false, err
+	}
+
+	password, err := generatePassword(24)
+	if err != nil {
+		return "", false, err
+	}
+
+	passwordHash, err := bcrypt.GenerateFromPassword([]byte(password), bcrypt.DefaultCost)
+	if err != nil {
+		return "", false, err
+	}
+
+	var userID string
+
+	err = db.QueryRow(
+		ctx,
+		`
+		INSERT INTO users (
+			username,
+			display_name,
+			email,
+			password_hash,
+			avatar,
+			unit,
+			user_group,
+			rights
+		)
+		VALUES ($1, $2, $3, $4, $5, $6, $7, $8::TEXT[])
+		RETURNING id
+		`,
+		adminUsername,
+		adminDisplayName,
+		adminEmail,
+		string(passwordHash),
+		adminAvatar,
+		adminUnit,
+		adminGroup,
+		toPostgresTextArray(adminRights),
+	).Scan(&userID)
+
+	if err != nil {
+		return "", false, err
+	}
+
+	if err := assignUserToTeam(ctx, db, userID, teamID); err != nil {
+		return "", false, err
+	}
+
+	return password, true, nil
+}
+
+func ensureTeam(ctx context.Context, db *pgxpool.Pool, name string, initial string, href string) (string, error) {
+	name = strings.TrimSpace(name)
+	initial = strings.TrimSpace(initial)
+	href = strings.TrimSpace(href)
+
+	if name == "" {
+		name = "Administration"
+	}
+
+	if initial == "" {
+		initial = strings.ToUpper(string([]rune(name)[0]))
+	}
+
+	if href == "" {
+		href = "#"
+	}
+
+	var teamID string
+
+	err := db.QueryRow(
+		ctx,
+		`
+		INSERT INTO teams (name, initial, href)
+		VALUES ($1, $2, $3)
+		ON CONFLICT (name)
+		DO UPDATE SET
+			initial = EXCLUDED.initial,
+			href = EXCLUDED.href,
+			updated_at = now()
+		RETURNING id
+		`,
+		name,
+		initial,
+		href,
+	).Scan(&teamID)
+
+	return teamID, err
+}
+
+func assignUserToTeam(ctx context.Context, db *pgxpool.Pool, userID string, teamID string) error {
+	_, err := db.Exec(
+		ctx,
+		`
+		INSERT INTO user_teams (user_id, team_id)
+		VALUES ($1, $2)
+		ON CONFLICT (user_id, team_id) DO NOTHING
+		`,
+		userID,
+		teamID,
+	)
+
+	return err
+}
+
+func generatePassword(length int) (string, error) {
+	randomBytes := make([]byte, length)
+
+	if _, err := rand.Read(randomBytes); err != nil {
+		return "", err
+	}
+
+	password := base64.RawURLEncoding.EncodeToString(randomBytes)
+
+	if len(password) > length {
+		password = password[:length]
+	}
+
+	return password, nil
+}
+
+func printAdminResult(password string, created bool) {
+	adminUsername := env("ADMIN_USERNAME", "admin")
+	adminEmail := env("ADMIN_EMAIL", "admin@example.com")
+	adminTeamName := env("ADMIN_TEAM_NAME", "Administration")
+
+	fmt.Println("")
+
+	if created {
+		fmt.Println("=================================================")
+		fmt.Println("Admin-User wurde erstellt")
+		fmt.Println("=================================================")
+		fmt.Printf("Benutzername: %s\n", adminUsername)
+		fmt.Printf("E-Mail:       %s\n", adminEmail)
+		fmt.Printf("Team:         %s\n", adminTeamName)
+		fmt.Printf("Passwort:     %s\n", password)
+		fmt.Println("=================================================")
+		fmt.Println("Bitte Passwort sicher speichern. Es wird nicht erneut angezeigt.")
+		fmt.Println("")
+		return
+	}
+
+	fmt.Println("=================================================")
+	fmt.Println("Admin-User existiert bereits")
+	fmt.Println("=================================================")
+	fmt.Printf("Benutzername: %s\n", adminUsername)
+	fmt.Printf("E-Mail:       %s\n", adminEmail)
+	fmt.Printf("Team:         %s\n", adminTeamName)
+	fmt.Println("Passwort:     wird nicht angezeigt, da nur der Hash gespeichert wird")
+	fmt.Println("=================================================")
+	fmt.Println("")
+}
+
+func toPostgresTextArray(values []string) string {
+	if len(values) == 0 {
+		return "{}"
+	}
+
+	escaped := make([]string, 0, len(values))
+
+	for _, value := range values {
+		value = strings.TrimSpace(value)
+
+		if value == "" {
+			continue
+		}
+
+		value = strings.ReplaceAll(value, `\`, `\\`)
+		value = strings.ReplaceAll(value, `"`, `\"`)
+
+		escaped = append(escaped, `"`+value+`"`)
+	}
+
+	if len(escaped) == 0 {
+		return "{}"
+	}
+
+	return "{" + strings.Join(escaped, ",") + "}"
+}
+
+func splitCSV(value string) []string {
+	parts := strings.Split(value, ",")
+	result := make([]string, 0, len(parts))
+
+	for _, part := range parts {
+		part = strings.TrimSpace(part)
+
+		if part != "" {
+			result = append(result, part)
+		}
+	}
+
+	return result
+}
+
+func quoteIdentifier(value string) string {
+	return `"` + strings.ReplaceAll(value, `"`, `""`) + `"`
+}
+
+func env(key string, fallback string) string {
+	value := os.Getenv(key)
+
+	if value == "" {
+		return fallback
+	}
+
+	return value
+}

frontend/.gitignore

@@ -0,0 +1,24 @@
+# Logs
+logs
+*.log
+npm-debug.log*
+yarn-debug.log*
+yarn-error.log*
+pnpm-debug.log*
+lerna-debug.log*
+
+node_modules
+dist
+dist-ssr
+*.local
+
+# Editor directories and files
+.vscode/*
+!.vscode/extensions.json
+.idea
+.DS_Store
+*.suo
+*.ntvs*
+*.njsproj
+*.sln
+*.sw?

frontend/README.md

@@ -0,0 +1,73 @@
+# React + TypeScript + Vite
+
+This template provides a minimal setup to get React working in Vite with HMR and some ESLint rules.
+
+Currently, two official plugins are available:
+
+- [@vitejs/plugin-react](https://github.com/vitejs/vite-plugin-react/blob/main/packages/plugin-react) uses [Oxc](https://oxc.rs)
+- [@vitejs/plugin-react-swc](https://github.com/vitejs/vite-plugin-react/blob/main/packages/plugin-react-swc) uses [SWC](https://swc.rs/)
+
+## React Compiler
+
+The React Compiler is not enabled on this template because of its impact on dev & build performances. To add it, see [this documentation](https://react.dev/learn/react-compiler/installation).
+
+## Expanding the ESLint configuration
+
+If you are developing a production application, we recommend updating the configuration to enable type-aware lint rules:
+
+```js
+export default defineConfig([
+  globalIgnores(['dist']),
+  {
+    files: ['**/*.{ts,tsx}'],
+    extends: [
+      // Other configs...
+
+      // Remove tseslint.configs.recommended and replace with this
+      tseslint.configs.recommendedTypeChecked,
+      // Alternatively, use this for stricter rules
+      tseslint.configs.strictTypeChecked,
+      // Optionally, add this for stylistic rules
+      tseslint.configs.stylisticTypeChecked,
+
+      // Other configs...
+    ],
+    languageOptions: {
+      parserOptions: {
+        project: ['./tsconfig.node.json', './tsconfig.app.json'],
+        tsconfigRootDir: import.meta.dirname,
+      },
+      // other options...
+    },
+  },
+])
+```
+
+You can also install [eslint-plugin-react-x](https://github.com/Rel1cx/eslint-react/tree/main/packages/plugins/eslint-plugin-react-x) and [eslint-plugin-react-dom](https://github.com/Rel1cx/eslint-react/tree/main/packages/plugins/eslint-plugin-react-dom) for React-specific lint rules:
+
+```js
+// eslint.config.js
+import reactX from 'eslint-plugin-react-x'
+import reactDom from 'eslint-plugin-react-dom'
+
+export default defineConfig([
+  globalIgnores(['dist']),
+  {
+    files: ['**/*.{ts,tsx}'],
+    extends: [
+      // Other configs...
+      // Enable lint rules for React
+      reactX.configs['recommended-typescript'],
+      // Enable lint rules for React DOM
+      reactDom.configs.recommended,
+    ],
+    languageOptions: {
+      parserOptions: {
+        project: ['./tsconfig.node.json', './tsconfig.app.json'],
+        tsconfigRootDir: import.meta.dirname,
+      },
+      // other options...
+    },
+  },
+])
+```

frontend/eslint.config.js

@@ -0,0 +1,22 @@
+import js from '@eslint/js'
+import globals from 'globals'
+import reactHooks from 'eslint-plugin-react-hooks'
+import reactRefresh from 'eslint-plugin-react-refresh'
+import tseslint from 'typescript-eslint'
+import { defineConfig, globalIgnores } from 'eslint/config'
+
+export default defineConfig([
+  globalIgnores(['dist']),
+  {
+    files: ['**/*.{ts,tsx}'],
+    extends: [
+      js.configs.recommended,
+      tseslint.configs.recommended,
+      reactHooks.configs.flat.recommended,
+      reactRefresh.configs.vite,
+    ],
+    languageOptions: {
+      globals: globals.browser,
+    },
+  },
+])

frontend/index.html

@@ -0,0 +1,13 @@
+<!doctype html>
+<html class="bg-white dark:bg-gray-950 scheme-light dark:scheme-dark">
+  <head>
+    <meta charset="UTF-8" />
+    <link rel="icon" type="image/svg+xml" href="/favicon.svg" />
+    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
+    <title>teg</title>
+  </head>
+  <body>
+    <div id="root"></div>
+    <script type="module" src="/src/main.tsx"></script>
+  </body>
+</html>

frontend/package.json

@@ -0,0 +1,35 @@
+{
+  "name": "teg",
+  "private": true,
+  "version": "0.0.0",
+  "type": "module",
+  "scripts": {
+    "dev": "vite",
+    "build": "tsc -b && vite build",
+    "lint": "eslint .",
+    "preview": "vite preview"
+  },
+  "dependencies": {
+    "@headlessui/react": "^2.2.10",
+    "@heroicons/react": "^2.2.0",
+    "@tailwindcss/vite": "^4.3.0",
+    "react": "^19.2.6",
+    "react-dom": "^19.2.6",
+    "react-router": "^7.15.0",
+    "tailwindcss": "^4.3.0"
+  },
+  "devDependencies": {
+    "@eslint/js": "^10.0.1",
+    "@types/node": "^24.12.3",
+    "@types/react": "^19.2.14",
+    "@types/react-dom": "^19.2.3",
+    "@vitejs/plugin-react": "^6.0.1",
+    "eslint": "^10.3.0",
+    "eslint-plugin-react-hooks": "^7.1.1",
+    "eslint-plugin-react-refresh": "^0.5.2",
+    "globals": "^17.6.0",
+    "typescript": "~6.0.2",
+    "typescript-eslint": "^8.59.2",
+    "vite": "^8.0.12"
+  }
+}

frontend/public/icons.svg

@@ -0,0 +1,24 @@
+<svg xmlns="http://www.w3.org/2000/svg">
+  <symbol id="bluesky-icon" viewBox="0 0 16 17">
+    <g clip-path="url(#bluesky-clip)"><path fill="#08060d" d="M7.75 7.735c-.693-1.348-2.58-3.86-4.334-5.097-1.68-1.187-2.32-.981-2.74-.79C.188 2.065.1 2.812.1 3.251s.241 3.602.398 4.13c.52 1.744 2.367 2.333 4.07 2.145-2.495.37-4.71 1.278-1.805 4.512 3.196 3.309 4.38-.71 4.987-2.746.608 2.036 1.307 5.91 4.93 2.746 2.72-2.746.747-4.143-1.747-4.512 1.702.189 3.55-.4 4.07-2.145.156-.528.397-3.691.397-4.13s-.088-1.186-.575-1.406c-.42-.19-1.06-.395-2.741.79-1.755 1.24-3.64 3.752-4.334 5.099"/></g>
+    <defs><clipPath id="bluesky-clip"><path fill="#fff" d="M.1.85h15.3v15.3H.1z"/></clipPath></defs>
+  </symbol>
+  <symbol id="discord-icon" viewBox="0 0 20 19">
+    <path fill="#08060d" d="M16.224 3.768a14.5 14.5 0 0 0-3.67-1.153c-.158.286-.343.67-.47.976a13.5 13.5 0 0 0-4.067 0c-.128-.306-.317-.69-.476-.976A14.4 14.4 0 0 0 3.868 3.77C1.546 7.28.916 10.703 1.231 14.077a14.7 14.7 0 0 0 4.5 2.306q.545-.748.965-1.587a9.5 9.5 0 0 1-1.518-.74q.191-.14.372-.293c2.927 1.369 6.107 1.369 8.999 0q.183.152.372.294-.723.437-1.52.74.418.838.963 1.588a14.6 14.6 0 0 0 4.504-2.308c.37-3.911-.63-7.302-2.644-10.309m-9.13 8.234c-.878 0-1.599-.82-1.599-1.82 0-.998.705-1.82 1.6-1.82.894 0 1.614.82 1.599 1.82.001 1-.705 1.82-1.6 1.82m5.91 0c-.878 0-1.599-.82-1.599-1.82 0-.998.705-1.82 1.6-1.82.893 0 1.614.82 1.599 1.82 0 1-.706 1.82-1.6 1.82"/>
+  </symbol>
+  <symbol id="documentation-icon" viewBox="0 0 21 20">
+    <path fill="none" stroke="#aa3bff" stroke-linecap="round" stroke-linejoin="round" stroke-width="1.35" d="m15.5 13.333 1.533 1.322c.645.555.967.833.967 1.178s-.322.623-.967 1.179L15.5 18.333m-3.333-5-1.534 1.322c-.644.555-.966.833-.966 1.178s.322.623.966 1.179l1.534 1.321"/>
+    <path fill="none" stroke="#aa3bff" stroke-linecap="round" stroke-linejoin="round" stroke-width="1.35" d="M17.167 10.836v-4.32c0-1.41 0-2.117-.224-2.68-.359-.906-1.118-1.621-2.08-1.96-.599-.21-1.349-.21-2.848-.21-2.623 0-3.935 0-4.983.369-1.684.591-3.013 1.842-3.641 3.428C3 6.449 3 7.684 3 10.154v2.122c0 2.558 0 3.838.706 4.726q.306.383.713.671c.76.536 1.79.64 3.581.66"/>
+    <path fill="none" stroke="#aa3bff" stroke-linecap="round" stroke-linejoin="round" stroke-width="1.35" d="M3 10a2.78 2.78 0 0 1 2.778-2.778c.555 0 1.209.097 1.748-.047.48-.129.854-.503.982-.982.145-.54.048-1.194.048-1.749a2.78 2.78 0 0 1 2.777-2.777"/>
+  </symbol>
+  <symbol id="github-icon" viewBox="0 0 19 19">
+    <path fill="#08060d" fill-rule="evenodd" d="M9.356 1.85C5.05 1.85 1.57 5.356 1.57 9.694a7.84 7.84 0 0 0 5.324 7.44c.387.079.528-.168.528-.376 0-.182-.013-.805-.013-1.454-2.165.467-2.616-.935-2.616-.935-.349-.91-.864-1.143-.864-1.143-.71-.48.051-.48.051-.48.787.051 1.2.805 1.2.805.695 1.194 1.817.857 2.268.649.064-.507.27-.857.49-1.052-1.728-.182-3.545-.857-3.545-3.87 0-.857.31-1.558.8-2.104-.078-.195-.349-1 .077-2.078 0 0 .657-.208 2.14.805a7.5 7.5 0 0 1 1.946-.26c.657 0 1.328.092 1.946.26 1.483-1.013 2.14-.805 2.14-.805.426 1.078.155 1.883.078 2.078.502.546.799 1.247.799 2.104 0 3.013-1.818 3.675-3.558 3.87.284.247.528.714.528 1.454 0 1.052-.012 1.896-.012 2.156 0 .208.142.455.528.377a7.84 7.84 0 0 0 5.324-7.441c.013-4.338-3.48-7.844-7.773-7.844" clip-rule="evenodd"/>
+  </symbol>
+  <symbol id="social-icon" viewBox="0 0 20 20">
+    <path fill="none" stroke="#aa3bff" stroke-linecap="round" stroke-linejoin="round" stroke-width="1.35" d="M12.5 6.667a4.167 4.167 0 1 0-8.334 0 4.167 4.167 0 0 0 8.334 0"/>
+    <path fill="none" stroke="#aa3bff" stroke-linecap="round" stroke-linejoin="round" stroke-width="1.35" d="M2.5 16.667a5.833 5.833 0 0 1 8.75-5.053m3.837.474.513 1.035c.07.144.257.282.414.309l.93.155c.596.1.736.536.307.965l-.723.73a.64.64 0 0 0-.152.531l.207.903c.164.715-.213.991-.84.618l-.872-.52a.63.63 0 0 0-.577 0l-.872.52c-.624.373-1.003.094-.84-.618l.207-.903a.64.64 0 0 0-.152-.532l-.723-.729c-.426-.43-.289-.864.306-.964l.93-.156a.64.64 0 0 0 .412-.31l.513-1.034c.28-.562.735-.562 1.012 0"/>
+  </symbol>
+  <symbol id="x-icon" viewBox="0 0 19 19">
+    <path fill="#08060d" fill-rule="evenodd" d="M1.893 1.98c.052.072 1.245 1.769 2.653 3.77l2.892 4.114c.183.261.333.48.333.486s-.068.089-.152.183l-.522.593-.765.867-3.597 4.087c-.375.426-.734.834-.798.905a1 1 0 0 0-.118.148c0 .01.236.017.664.017h.663l.729-.83c.4-.457.796-.906.879-.999a692 692 0 0 0 1.794-2.038c.034-.037.301-.34.594-.675l.551-.624.345-.392a7 7 0 0 1 .34-.374c.006 0 .93 1.306 2.052 2.903l2.084 2.965.045.063h2.275c1.87 0 2.273-.003 2.266-.021-.008-.02-1.098-1.572-3.894-5.547-2.013-2.862-2.28-3.246-2.273-3.266.008-.019.282-.332 2.085-2.38l2-2.274 1.567-1.782c.022-.028-.016-.03-.65-.03h-.674l-.3.342a871 871 0 0 1-1.782 2.025c-.067.075-.405.458-.75.852a100 100 0 0 1-.803.91c-.148.172-.299.344-.99 1.127-.304.343-.32.358-.345.327-.015-.019-.904-1.282-1.976-2.808L6.365 1.85H1.8zm1.782.91 8.078 11.294c.772 1.08 1.413 1.973 1.425 1.984.016.017.241.02 1.05.017l1.03-.004-2.694-3.766L7.796 5.75 5.722 2.852l-1.039-.004-1.039-.004z" clip-rule="evenodd"/>
+  </symbol>
+</svg>

frontend/src/App.css

@@ -0,0 +1 @@
+/* frontend\src\App.css */

frontend/src/App.tsx

@@ -0,0 +1,130 @@
+// frontend\src\App.tsx
+
+import { useEffect, useState, type FormEvent } from 'react'
+import { Navigate, Route, Routes } from 'react-router'
+import LoginForm from './components/LoginForm'
+import AppLayout from './components/AppLayout'
+import DashboardPage from './pages/DashboardPage'
+import DevicesPage from './pages/DevicesPage'
+import IncidentsPage from './pages/IncidentsPage'
+import CalendarPage from './pages/CalendarPage'
+import DocumentsPage from './pages/DocumentsPage'
+import ReportsPage from './pages/ReportsPage'
+import SettingsPage from './pages/SettingsPage'
+import type { Team, User } from './components/types'
+import './App.css'
+
+const API_URL = import.meta.env.VITE_API_URL ?? 'http://localhost:8080'
+
+function App() {
+  const [user, setUser] = useState<User | null>(null)
+  const [isLoading, setIsLoading] = useState(true)
+  const [isLoggingIn, setIsLoggingIn] = useState(false)
+
+  useEffect(() => {
+    loadUser()
+  }, [])
+
+  async function loadUser() {
+    try {
+      const response = await fetch(`${API_URL}/auth/me`, {
+        credentials: 'include',
+      })
+
+      if (!response.ok) {
+        setUser(null)
+        return
+      }
+
+      const data = await response.json()
+      setUser(data.user)
+    } catch {
+      setUser(null)
+    } finally {
+      setIsLoading(false)
+    }
+  }
+
+  async function handleLogin(event: FormEvent<HTMLFormElement>) {
+    event.preventDefault()
+
+    setIsLoggingIn(true)
+
+    const formData = new FormData(event.currentTarget)
+
+    const identifier = String(formData.get('identifier'))
+    const password = String(formData.get('password'))
+
+    try {
+      const response = await fetch(`${API_URL}/auth/login`, {
+        method: 'POST',
+        headers: {
+          'Content-Type': 'application/json',
+        },
+        credentials: 'include',
+        body: JSON.stringify({ identifier, password }),
+      })
+
+      if (!response.ok) {
+        const errorData = await response.json().catch(() => null)
+        alert(errorData?.error ?? 'Login fehlgeschlagen')
+        return
+      }
+
+      const data = await response.json()
+      setUser(data.user)
+    } catch {
+      alert('Backend ist nicht erreichbar')
+    } finally {
+      setIsLoggingIn(false)
+    }
+  }
+
+  async function handleLogout() {
+    try {
+      await fetch(`${API_URL}/auth/logout`, {
+        method: 'POST',
+        credentials: 'include',
+      })
+    } finally {
+      setUser(null)
+    }
+  }
+
+  if (isLoading) {
+    return (
+      <div className="flex min-h-screen items-center justify-center bg-gray-50 dark:bg-gray-900">
+        <p className="text-sm text-gray-500 dark:text-gray-400">
+          Loading...
+        </p>
+      </div>
+    )
+  }
+
+  if (!user) {
+    return (
+      <LoginForm
+        onSubmit={handleLogin}
+        submitText="Anmelden"
+        isSubmitting={isLoggingIn}
+      />
+    )
+  }
+
+  return (
+    <AppLayout user={user} onLogout={handleLogout}>
+      <Routes>
+        <Route path="/" element={<DashboardPage username={user.username} />} />
+        <Route path="/geraete" element={<DevicesPage />} />
+        <Route path="/einsaetze" element={<IncidentsPage />} />
+        <Route path="/kalender" element={<CalendarPage />} />
+        <Route path="/dokumente" element={<DocumentsPage />} />
+        <Route path="/berichte" element={<ReportsPage />} />
+        <Route path="/einstellungen/*" element={<SettingsPage user={user} />} />
+        <Route path="*" element={<Navigate to="/" replace />} />
+      </Routes>
+    </AppLayout>
+  )
+}
+
+export default App

frontend/src/components/AppLayout.tsx

@@ -0,0 +1,38 @@
+// frontend\src\components\AppLayout.tsx
+
+import { useState, type ReactNode } from 'react'
+import Sidebar from './Sidebar'
+import Topbar from './Topbar'
+import type { User } from './types'
+
+type AppLayoutProps = {
+  user: User
+  onLogout: () => void | Promise<void>
+  children: ReactNode
+}
+
+export default function AppLayout({ user, onLogout, children }: AppLayoutProps) {
+  const [sidebarOpen, setSidebarOpen] = useState(false)
+
+  return (
+    <div>
+      <Sidebar
+        user={user}
+        sidebarOpen={sidebarOpen}
+        setSidebarOpen={setSidebarOpen}
+      />
+
+      <div className="lg:pl-72">
+        <Topbar
+          user={user}
+          onLogout={onLogout}
+          onOpenSidebar={() => setSidebarOpen(true)}
+        />
+
+        <main>
+          {children}
+        </main>
+      </div>
+    </div>
+  )
+}

frontend/src/components/Button.tsx

@@ -0,0 +1,200 @@
+// frontend\src\components\ui\Button.tsx
+
+import { type ButtonHTMLAttributes, type ReactNode } from 'react'
+
+type Variant = 'primary' | 'secondary' | 'soft'
+type Size = 'xs' | 'sm' | 'md' | 'lg'
+type Color = 'indigo' | 'blue' | 'emerald' | 'red' | 'amber'
+
+export type ButtonProps = Omit<
+  ButtonHTMLAttributes<HTMLButtonElement>,
+  'children'
+> & {
+  children: ReactNode
+  variant?: Variant
+  size?: Size
+  color?: Color
+  rounded?: 'sm' | 'md' | 'full'
+  leadingIcon?: ReactNode
+  trailingIcon?: ReactNode
+  isLoading?: boolean
+  className?: string
+}
+
+function cn(...parts: Array<string | false | null | undefined>) {
+  return parts.filter(Boolean).join(' ')
+}
+
+const base =
+  'inline-flex items-center justify-center font-semibold transition-colors duration-150 focus-visible:outline-2 focus-visible:outline-offset-2 ' +
+  'disabled:cursor-not-allowed disabled:saturate-0 disabled:opacity-60 disabled:hover:brightness-100'
+
+const disabledPrimary =
+  'disabled:!bg-gray-300 disabled:!text-gray-600 disabled:shadow-none disabled:hover:!bg-gray-300 ' +
+  'dark:disabled:!bg-white/10 dark:disabled:!text-white/40 dark:disabled:hover:!bg-white/10'
+
+const disabledSecondary =
+  'disabled:bg-gray-100 disabled:text-gray-500 disabled:ring-gray-300 disabled:shadow-none disabled:hover:bg-gray-100 ' +
+  'dark:disabled:bg-white/5 dark:disabled:text-white/40 dark:disabled:ring-white/10 dark:disabled:hover:bg-white/5'
+
+const disabledSoft =
+  'disabled:bg-gray-100 disabled:text-gray-500 disabled:inset-ring-gray-200 disabled:shadow-none disabled:hover:bg-gray-100 ' +
+  'dark:disabled:bg-white/5 dark:disabled:text-white/40 dark:disabled:hover:bg-white/5'
+
+const roundedMap = {
+  sm: 'rounded-sm',
+  md: 'rounded-md',
+  full: 'rounded-full',
+} as const
+
+const sizeMap: Record<Size, string> = {
+  xs: 'px-2 py-1 text-xs',
+  sm: 'px-2.5 py-1.5 text-sm',
+  md: 'px-3 py-2 text-sm',
+  lg: 'px-3.5 py-2.5 text-sm',
+}
+
+const colorMap: Record<Color, Record<Variant, string>> = {
+  indigo: {
+    primary:
+      '!bg-indigo-600 !text-white shadow-sm hover:!bg-indigo-500 focus-visible:outline-indigo-600 ' +
+      'dark:!bg-indigo-500 dark:hover:!bg-indigo-400 dark:focus-visible:outline-indigo-500 ' +
+      disabledPrimary,
+    secondary:
+      'bg-white text-gray-900 shadow-xs ring-1 ring-gray-200 hover:bg-indigo-50 hover:text-indigo-700 hover:ring-indigo-200 ' +
+      'dark:bg-white/10 dark:text-white dark:shadow-none dark:ring-white/10 dark:hover:bg-indigo-500/15 dark:hover:text-indigo-300 dark:hover:ring-indigo-400/20 ' +
+      disabledSecondary,
+    soft:
+      'bg-indigo-500/14 text-indigo-700 shadow-xs inset-ring inset-ring-indigo-500/20 hover:bg-indigo-500/20 hover:inset-ring-indigo-500/25 ' +
+      'dark:bg-indigo-500/20 dark:text-indigo-400 dark:shadow-none dark:inset-ring-0 dark:hover:bg-indigo-500/25 ' +
+      disabledSoft,
+  },
+
+  blue: {
+    primary:
+      '!bg-blue-600 !text-white shadow-sm hover:!bg-blue-500 focus-visible:outline-blue-600 ' +
+      'dark:!bg-blue-500 dark:hover:!bg-blue-400 dark:focus-visible:outline-blue-500 ' +
+      disabledPrimary,
+    secondary:
+      'bg-white text-gray-900 shadow-xs ring-1 ring-gray-200 hover:bg-blue-50 hover:text-blue-700 hover:ring-blue-200 ' +
+      'dark:bg-white/10 dark:text-white dark:shadow-none dark:ring-white/10 dark:hover:bg-blue-500/15 dark:hover:text-blue-300 dark:hover:ring-blue-400/20 ' +
+      disabledSecondary,
+    soft:
+      'bg-blue-500/14 text-blue-700 shadow-xs inset-ring inset-ring-blue-500/20 hover:bg-blue-500/20 hover:inset-ring-blue-500/25 ' +
+      'dark:bg-blue-500/20 dark:text-blue-400 dark:shadow-none dark:inset-ring-0 dark:hover:bg-blue-500/25 ' +
+      disabledSoft,
+  },
+
+  emerald: {
+    primary:
+      '!bg-emerald-600 !text-white shadow-sm hover:!bg-emerald-500 focus-visible:outline-emerald-600 ' +
+      'dark:!bg-emerald-500 dark:hover:!bg-emerald-400 dark:focus-visible:outline-emerald-500 ' +
+      disabledPrimary,
+    secondary:
+      'bg-white text-gray-900 shadow-xs ring-1 ring-gray-200 hover:bg-emerald-50 hover:text-emerald-700 hover:ring-emerald-200 ' +
+      'dark:bg-white/10 dark:text-white dark:shadow-none dark:ring-white/10 dark:hover:bg-emerald-500/15 dark:hover:text-emerald-300 dark:hover:ring-emerald-400/20 ' +
+      disabledSecondary,
+    soft:
+      'bg-emerald-500/14 text-emerald-700 shadow-xs inset-ring inset-ring-emerald-500/20 hover:bg-emerald-500/20 hover:inset-ring-emerald-500/25 ' +
+      'dark:bg-emerald-500/20 dark:text-emerald-400 dark:shadow-none dark:inset-ring-0 dark:hover:bg-emerald-500/25 ' +
+      disabledSoft,
+  },
+
+  red: {
+    primary:
+      '!bg-red-600 !text-white shadow-sm hover:!bg-red-500 focus-visible:outline-red-600 ' +
+      'dark:!bg-red-500 dark:hover:!bg-red-400 dark:focus-visible:outline-red-500 ' +
+      disabledPrimary,
+    secondary:
+      'bg-white text-gray-900 shadow-xs ring-1 ring-gray-200 hover:bg-red-50 hover:text-red-700 hover:ring-red-200 ' +
+      'dark:bg-white/10 dark:text-white dark:shadow-none dark:ring-white/10 dark:hover:bg-red-500/15 dark:hover:text-red-300 dark:hover:ring-red-400/20 ' +
+      disabledSecondary,
+    soft:
+      'bg-red-500/14 text-red-700 shadow-xs inset-ring inset-ring-red-500/20 hover:bg-red-500/20 hover:inset-ring-red-500/25 ' +
+      'dark:bg-red-500/20 dark:text-red-400 dark:shadow-none dark:inset-ring-0 dark:hover:bg-red-500/25 ' +
+      disabledSoft,
+  },
+
+  amber: {
+    primary:
+      '!bg-amber-500 !text-white shadow-sm hover:!bg-amber-400 focus-visible:outline-amber-500 ' +
+      'dark:!bg-amber-500 dark:hover:!bg-amber-400 dark:focus-visible:outline-amber-500 ' +
+      disabledPrimary,
+    secondary:
+      'bg-white text-gray-900 shadow-xs ring-1 ring-gray-200 hover:bg-amber-50 hover:text-amber-800 hover:ring-amber-200 ' +
+      'dark:bg-white/10 dark:text-white dark:shadow-none dark:ring-white/10 dark:hover:bg-amber-500/15 dark:hover:text-amber-300 dark:hover:ring-amber-400/20 ' +
+      disabledSecondary,
+    soft:
+      'bg-amber-500/12 text-amber-800 shadow-xs inset-ring inset-ring-amber-500/20 hover:bg-amber-500/18 hover:inset-ring-amber-500/25 ' +
+      'dark:bg-amber-500/20 dark:text-amber-300 dark:shadow-none dark:inset-ring-0 dark:hover:bg-amber-500/25 ' +
+      disabledSoft,
+  },
+}
+
+function Spinner() {
+  return (
+    <svg viewBox="0 0 24 24" className="size-4 animate-spin" aria-hidden="true">
+      <circle
+        cx="12"
+        cy="12"
+        r="10"
+        fill="none"
+        stroke="currentColor"
+        strokeWidth="4"
+        opacity="0.25"
+      />
+      <path
+        d="M22 12a10 10 0 0 1-10 10"
+        fill="none"
+        stroke="currentColor"
+        strokeWidth="4"
+        opacity="0.9"
+      />
+    </svg>
+  )
+}
+
+export default function Button({
+  children,
+  variant = 'primary',
+  color = 'indigo',
+  size = 'md',
+  rounded = 'md',
+  leadingIcon,
+  trailingIcon,
+  isLoading = false,
+  disabled,
+  className,
+  type = 'button',
+  ...props
+}: ButtonProps) {
+  const iconGap = leadingIcon || trailingIcon || isLoading ? 'gap-x-1.5' : ''
+
+  return (
+    <button
+      type={type}
+      disabled={disabled || isLoading}
+      className={cn(
+        base,
+        roundedMap[rounded],
+        sizeMap[size],
+        colorMap[color][variant],
+        iconGap,
+        className
+      )}
+      {...props}
+    >
+      {isLoading ? (
+        <span className="-ml-0.5">
+          <Spinner />
+        </span>
+      ) : (
+        leadingIcon && <span className="-ml-0.5">{leadingIcon}</span>
+      )}
+
+      <span>{children}</span>
+
+      {trailingIcon && !isLoading && <span className="-mr-0.5">{trailingIcon}</span>}
+    </button>
+  )
+}

frontend/src/components/ButtonGroup.tsx

@@ -0,0 +1,116 @@
+// components/ui/ButtonGroup.tsx
+'use client'
+
+import { type ReactNode } from 'react'
+
+type Size = 'sm' | 'md' | 'lg'
+
+export type ButtonGroupItem = {
+  id: string
+  label?: ReactNode
+  icon?: ReactNode
+  srLabel?: string
+  disabled?: boolean
+}
+
+export type ButtonGroupProps = {
+  items: ButtonGroupItem[]
+  value: string
+  onChange: (id: string) => void
+  size?: Size
+  className?: string
+  ariaLabel?: string
+}
+
+function cn(...parts: Array<string | false | null | undefined>) {
+  return parts.filter(Boolean).join(' ')
+}
+
+const sizeMap: Record<Size, { btn: string; icon: string; iconOnly: string }> = {
+  sm: { btn: 'px-2.5 py-1.5 text-sm', icon: 'size-5', iconOnly: 'h-9 w-9' },
+  md: { btn: 'px-3 py-2 text-sm', icon: 'size-5', iconOnly: 'h-10 w-10' },
+  lg: { btn: 'px-3.5 py-2.5 text-sm', icon: 'size-5', iconOnly: 'h-11 w-11' },
+}
+
+export default function ButtonGroup({
+  items,
+  value,
+  onChange,
+  size = 'md',
+  className,
+  ariaLabel = 'Optionen',
+}: ButtonGroupProps) {
+  const s = sizeMap[size]
+
+  return (
+    <span
+      className={cn(
+        'isolate inline-flex overflow-hidden rounded-md shadow-xs ring-1 ring-gray-300 dark:shadow-none dark:ring-gray-700',
+        className
+      )}
+      role="group"
+      aria-label={ariaLabel}
+    >
+      {items.map((it, idx) => {
+        const active = it.id === value
+        const isFirst = idx === 0
+        const isLast = idx === items.length - 1
+        const iconOnly = !it.label && !!it.icon
+
+        return (
+          <button
+            key={it.id}
+            type="button"
+            disabled={it.disabled}
+            onClick={() => onChange(it.id)}
+            aria-pressed={active}
+            className={cn(
+              'relative inline-flex items-center justify-center font-semibold leading-none',
+              'transition-[background-color,color,box-shadow] duration-150',
+              'focus:z-20 hover:z-10',
+              !isFirst && 'before:absolute before:bottom-0 before:left-0 before:top-0 before:w-px before:bg-gray-300 dark:before:bg-gray-700',
+              isFirst && 'rounded-l-md',
+              isLast && 'rounded-r-md',
+
+              active
+                ? [
+                    'bg-indigo-100 text-indigo-800',
+                    'hover:bg-indigo-200',
+                    'hover:shadow-[inset_0_0_0_1px_rgba(99,102,241,0.28),inset_0_0_0_9999px_rgba(99,102,241,0.10)]',
+                    'dark:bg-indigo-500/40 dark:text-indigo-100 dark:hover:bg-indigo-500/50 dark:hover:shadow-none',
+                  ].join(' ')
+                : [
+                    'bg-white text-gray-900',
+                    'hover:bg-gray-50',
+                    'hover:shadow-[inset_0_0_0_1px_rgba(148,163,184,0.35),inset_0_0_0_9999px_rgba(15,23,42,0.05)]',
+                    'dark:bg-white/10 dark:text-white dark:hover:bg-white/20 dark:hover:shadow-none',
+                  ].join(' '),
+
+              'disabled:cursor-not-allowed disabled:opacity-50 disabled:hover:shadow-none',
+              iconOnly ? `p-0 ${s.iconOnly}` : s.btn
+            )}
+            title={typeof it.label === 'string' ? it.label : it.srLabel}
+          >
+            {iconOnly && it.srLabel ? <span className="sr-only">{it.srLabel}</span> : null}
+
+            {it.icon ? (
+              <span
+                className={cn(
+                  'shrink-0 transition-colors duration-150',
+                  iconOnly ? '' : '-ml-0.5',
+                  active
+                    ? 'text-indigo-700 dark:text-indigo-200'
+                    : 'text-gray-500 dark:text-gray-500'
+                )}
+              >
+                {it.icon}
+              </span>
+            ) : null}
+
+            {it.label ? <span className={it.icon ? 'ml-1.5' : ''}>{it.label}</span> : null}
+          </button>
+        )
+      })}
+    </span>
+  )
+}

frontend/src/components/Camera.tsx

@@ -0,0 +1,235 @@
+// frontend\src\components\Camera.tsx
+
+import { useEffect, useRef, useState } from 'react'
+import { Dialog, DialogBackdrop, DialogPanel, DialogTitle } from '@headlessui/react'
+import { CameraIcon, XMarkIcon } from '@heroicons/react/24/outline'
+
+type BarcodeDetectorResult = {
+  rawValue: string
+}
+
+type BarcodeDetectorInstance = {
+  detect: (source: HTMLVideoElement) => Promise<BarcodeDetectorResult[]>
+}
+
+type BarcodeDetectorConstructor = new (options?: {
+  formats?: string[]
+}) => BarcodeDetectorInstance
+
+type CameraProps = {
+  onScan?: (value: string) => void
+}
+
+export default function Camera({ onScan }: CameraProps) {
+  const [open, setOpen] = useState(false)
+  const [error, setError] = useState<string | null>(null)
+  const [scannedValue, setScannedValue] = useState<string | null>(null)
+  const [isStarting, setIsStarting] = useState(false)
+
+  const videoRef = useRef<HTMLVideoElement | null>(null)
+  const streamRef = useRef<MediaStream | null>(null)
+  const frameRef = useRef<number | null>(null)
+
+  useEffect(() => {
+    if (!open) {
+      stopCamera()
+      return
+    }
+
+    startCamera()
+
+    return () => {
+      stopCamera()
+    }
+  }, [open])
+
+  async function startCamera() {
+    setError(null)
+    setScannedValue(null)
+    setIsStarting(true)
+
+    try {
+      if (!navigator.mediaDevices?.getUserMedia) {
+        setError('Dein Browser unterstützt keinen Kamera-Zugriff.')
+        return
+      }
+
+      const stream = await navigator.mediaDevices.getUserMedia({
+        video: {
+          facingMode: {
+            ideal: 'environment',
+          },
+        },
+        audio: false,
+      })
+
+      streamRef.current = stream
+
+      if (videoRef.current) {
+        videoRef.current.srcObject = stream
+        await videoRef.current.play()
+      }
+
+      startQrScanner()
+    } catch {
+      setError('Kamera konnte nicht geöffnet werden. Bitte Berechtigung prüfen.')
+    } finally {
+      setIsStarting(false)
+    }
+  }
+
+  function stopCamera() {
+    if (frameRef.current) {
+      cancelAnimationFrame(frameRef.current)
+      frameRef.current = null
+    }
+
+    if (streamRef.current) {
+      streamRef.current.getTracks().forEach((track) => track.stop())
+      streamRef.current = null
+    }
+
+    if (videoRef.current) {
+      videoRef.current.srcObject = null
+    }
+  }
+
+  function startQrScanner() {
+    const BarcodeDetector = (
+      window as Window & {
+        BarcodeDetector?: BarcodeDetectorConstructor
+      }
+    ).BarcodeDetector
+
+    if (!BarcodeDetector) {
+      setError('QR-Code-Erkennung wird in diesem Browser nicht unterstützt. Die Kamera-Vorschau funktioniert trotzdem.')
+      return
+    }
+
+    const detector = new BarcodeDetector({
+      formats: ['qr_code'],
+    })
+
+    async function scan() {
+      if (!videoRef.current) return
+
+      try {
+        if (videoRef.current.readyState >= 2) {
+          const codes = await detector.detect(videoRef.current)
+
+          if (codes.length > 0) {
+            const value = codes[0].rawValue
+
+            setScannedValue(value)
+            onScan?.(value)
+            stopCamera()
+            return
+          }
+        }
+      } catch {
+        // Weiter versuchen, falls ein einzelner Frame nicht gelesen werden kann.
+      }
+
+      frameRef.current = requestAnimationFrame(scan)
+    }
+
+    frameRef.current = requestAnimationFrame(scan)
+  }
+
+  function closeModal() {
+    setOpen(false)
+  }
+
+  return (
+    <>
+      <button
+        type="button"
+        onClick={() => setOpen(true)}
+        className="-m-2.5 flex items-center justify-center p-2.5 text-gray-400 hover:text-gray-500 dark:text-gray-400 dark:hover:text-gray-300"
+      >
+        <span className="sr-only">QR-Code scannen</span>
+        <CameraIcon aria-hidden="true" className="size-6" />
+      </button>
+
+      <Dialog open={open} onClose={closeModal} className="relative z-50">
+        <DialogBackdrop
+          transition
+          className="fixed inset-0 bg-gray-500/75 transition-opacity data-closed:opacity-0 data-enter:duration-300 data-enter:ease-out data-leave:duration-200 data-leave:ease-in dark:bg-gray-900/70"
+        />
+
+        <div className="fixed inset-0 z-50 w-screen overflow-y-auto">
+          <div className="flex min-h-full items-end justify-center p-4 text-center sm:items-center sm:p-0">
+            <DialogPanel
+              transition
+              className="relative transform overflow-hidden rounded-lg bg-white text-left shadow-xl transition-all data-closed:translate-y-4 data-closed:opacity-0 data-enter:duration-300 data-enter:ease-out data-leave:duration-200 data-leave:ease-in sm:my-8 sm:w-full sm:max-w-lg data-closed:sm:translate-y-0 data-closed:sm:scale-95 dark:bg-gray-800 dark:outline dark:-outline-offset-1 dark:outline-white/10"
+            >
+              <div className="absolute top-0 right-0 pt-4 pr-4">
+                <button
+                  type="button"
+                  onClick={closeModal}
+                  className="rounded-md bg-white text-gray-400 hover:text-gray-500 focus:outline-2 focus:outline-offset-2 focus:outline-indigo-600 dark:bg-gray-800 dark:hover:text-gray-300 dark:focus:outline-white"
+                >
+                  <span className="sr-only">Schließen</span>
+                  <XMarkIcon aria-hidden="true" className="size-6" />
+                </button>
+              </div>
+
+              <div className="px-4 pt-5 pb-4 sm:p-6">
+                <DialogTitle as="h3" className="text-base font-semibold text-gray-900 dark:text-white">
+                  QR-Code scannen
+                </DialogTitle>
+
+                <p className="mt-2 text-sm text-gray-500 dark:text-gray-400">
+                  Richte die Kamera auf einen QR-Code.
+                </p>
+
+                <div className="mt-5 overflow-hidden rounded-lg bg-gray-950">
+                  {scannedValue ? (
+                    <div className="p-4">
+                      <p className="text-sm font-medium text-white">
+                        QR-Code erkannt:
+                      </p>
+                      <p className="mt-2 break-all rounded-md bg-white/10 p-3 text-sm text-white">
+                        {scannedValue}
+                      </p>
+                    </div>
+                  ) : (
+                    <video
+                      ref={videoRef}
+                      muted
+                      playsInline
+                      autoPlay
+                      className="aspect-video w-full object-cover"
+                    />
+                  )}
+                </div>
+
+                {isStarting && (
+                  <p className="mt-3 text-sm text-gray-500 dark:text-gray-400">
+                    Kamera wird gestartet...
+                  </p>
+                )}
+
+                {error && (
+                  <p className="mt-3 text-sm text-red-600 dark:text-red-400">
+                    {error}
+                  </p>
+                )}
+              </div>
+
+              <div className="bg-gray-50 px-4 py-3 sm:flex sm:flex-row-reverse sm:px-6 dark:bg-gray-700/25">
+                <button
+                  type="button"
+                  onClick={closeModal}
+                  className="inline-flex w-full justify-center rounded-md bg-indigo-600 px-3 py-2 text-sm font-semibold text-white shadow-xs hover:bg-indigo-500 sm:w-auto dark:bg-indigo-500 dark:shadow-none dark:hover:bg-indigo-400"
+                >
+                  Schließen
+                </button>
+              </div>
+            </DialogPanel>
+          </div>
+        </div>
+      </Dialog>
+    </>
+  )
+}

frontend/src/components/Card.tsx

@@ -0,0 +1,102 @@
+// frontend\src\components\Card.tsx
+
+import type { ReactNode } from 'react'
+
+type CardVariant =
+  | 'basic'
+  | 'edge-to-edge-mobile'
+  | 'with-header'
+  | 'with-footer'
+  | 'with-header-footer'
+  | 'gray-footer'
+  | 'gray-body'
+  | 'well'
+  | 'well-on-gray'
+  | 'well-edge-to-edge-mobile'
+
+type CardProps = {
+  children?: ReactNode
+  header?: ReactNode
+  footer?: ReactNode
+  variant?: CardVariant
+  className?: string
+}
+
+function classNames(...classes: Array<string | false | null | undefined>) {
+  return classes.filter(Boolean).join(' ')
+}
+
+export default function Card({
+  children,
+  header,
+  footer,
+  variant = 'basic',
+  className,
+}: CardProps) {
+  const isEdgeToEdgeMobile =
+    variant === 'edge-to-edge-mobile' || variant === 'well-edge-to-edge-mobile'
+
+  const isWell =
+    variant === 'well' ||
+    variant === 'well-on-gray' ||
+    variant === 'well-edge-to-edge-mobile'
+
+  const hasDivider =
+    variant === 'with-header' ||
+    variant === 'with-footer' ||
+    variant === 'with-header-footer'
+
+  const hasHeader =
+    header &&
+    (variant === 'with-header' ||
+      variant === 'with-header-footer' ||
+      variant === 'gray-body')
+
+  const hasFooter =
+    footer &&
+    (variant === 'with-footer' ||
+      variant === 'with-header-footer' ||
+      variant === 'gray-footer')
+
+  return (
+    <div
+      className={classNames(
+        'overflow-hidden',
+        isEdgeToEdgeMobile ? 'sm:rounded-lg' : 'rounded-lg',
+        isWell
+          ? variant === 'well-on-gray'
+            ? 'bg-gray-200 dark:bg-gray-800/50'
+            : 'bg-gray-50 dark:bg-gray-800/50'
+          : 'bg-white shadow-sm dark:bg-gray-800/50 dark:shadow-none dark:outline dark:-outline-offset-1 dark:outline-white/10',
+        hasDivider && 'divide-y divide-gray-200 dark:divide-white/10',
+        className,
+      )}
+    >
+      {hasHeader && (
+        <div className="px-4 py-5 sm:px-6">
+          {header}
+        </div>
+      )}
+
+      <div
+        className={classNames(
+          'px-4 py-5 sm:p-6',
+          variant === 'gray-body' && 'bg-gray-50 dark:bg-gray-800/50',
+        )}
+      >
+        {children}
+      </div>
+
+      {hasFooter && (
+        <div
+          className={classNames(
+            'px-4 py-4 sm:px-6',
+            variant === 'gray-footer' && 'bg-gray-50 dark:bg-gray-800/50',
+          )}
+        >
+          {footer}
+        </div>
+      )}
+    </div>
+  )
+}

frontend/src/components/Container.tsx

@@ -0,0 +1,48 @@
+import type { ReactNode } from 'react'
+
+type ContainerVariant =
+  | 'full-width-mobile'
+  | 'constrained'
+  | 'breakpoint-full-width-mobile'
+  | 'breakpoint-constrained'
+  | 'narrow'
+
+type ContainerProps = {
+  children: ReactNode
+  variant?: ContainerVariant
+  className?: string
+}
+
+function classNames(...classes: Array<string | false | null | undefined>) {
+  return classes.filter(Boolean).join(' ')
+}
+
+const variantClasses: Record<ContainerVariant, string> = {
+  'full-width-mobile': 'mx-auto max-w-7xl sm:px-6 lg:px-8',
+  constrained: 'mx-auto max-w-7xl px-4 sm:px-6 lg:px-8',
+  'breakpoint-full-width-mobile': 'container mx-auto sm:px-6 lg:px-8',
+  'breakpoint-constrained': 'container mx-auto px-4 sm:px-6 lg:px-8',
+  narrow: 'mx-auto max-w-7xl px-4 sm:px-6 lg:px-8',
+}
+
+export default function Container({
+  children,
+  variant = 'constrained',
+  className,
+}: ContainerProps) {
+  if (variant === 'narrow') {
+    return (
+      <div className={classNames(variantClasses[variant], className)}>
+        <div className="mx-auto max-w-3xl">
+          {children}
+        </div>
+      </div>
+    )
+  }
+
+  return (
+    <div className={classNames(variantClasses[variant], className)}>
+      {children}
+    </div>
+  )
+}

frontend/src/components/Feed.tsx

@@ -0,0 +1,689 @@
+// frontend/src/components/Feed.tsx
+
+import { Fragment, useState, type ComponentType, type FormEvent, type SVGProps } from 'react'
+import {
+  ChatBubbleLeftEllipsisIcon,
+  CheckIcon,
+  FaceFrownIcon,
+  FaceSmileIcon,
+  FireIcon,
+  HandThumbUpIcon,
+  HeartIcon,
+  PaperClipIcon,
+  TagIcon,
+  UserCircleIcon,
+  UserIcon,
+  XMarkIcon,
+} from '@heroicons/react/20/solid'
+import { CheckCircleIcon } from '@heroicons/react/24/solid'
+import { Label, Listbox, ListboxButton, ListboxOption, ListboxOptions } from '@headlessui/react'
+import Button from './Button'
+
+type FeedIcon = ComponentType<SVGProps<SVGSVGElement>>
+
+type FeedVariant = 'icons' | 'comments' | 'multiple'
+
+export type FeedTimelineItem = {
+  id: string | number
+  content: string
+  target: string
+  href: string
+  date: string
+  datetime: string
+  icon: FeedIcon
+  iconBackground: string
+}
+
+export type FeedCommentActivityItem =
+  | {
+      id: string | number
+      type: 'created' | 'edited' | 'sent' | 'viewed' | 'paid'
+      person: {
+        name: string
+      }
+      date: string
+      dateTime: string
+    }
+  | {
+      id: string | number
+      type: 'commented'
+      person: {
+        name: string
+        imageUrl: string
+      }
+      comment: string
+      date: string
+      dateTime: string
+    }
+
+export type FeedMultipleActivityItem =
+  | {
+      id: string | number
+      type: 'comment'
+      person: {
+        name: string
+        href: string
+      }
+      imageUrl: string
+      comment: string
+      date: string
+    }
+  | {
+      id: string | number
+      type: 'assignment'
+      person: {
+        name: string
+        href: string
+      }
+      assigned: {
+        name: string
+        href: string
+      }
+      date: string
+    }
+  | {
+      id: string | number
+      type: 'tags'
+      person: {
+        name: string
+        href: string
+      }
+      tags: Array<{
+        name: string
+        href: string
+        color: string
+      }>
+      date: string
+    }
+
+type Mood = {
+  name: string
+  value: string | null
+  icon: FeedIcon
+  iconColor: string
+  bgColor: string
+}
+
+type FeedProps = {
+  variant?: FeedVariant
+  timeline?: FeedTimelineItem[]
+  activity?: FeedCommentActivityItem[]
+  multipleActivity?: FeedMultipleActivityItem[]
+  currentUserAvatar?: string
+  showCommentForm?: boolean
+  onCommentSubmit?: (comment: string, mood: Mood) => void
+  className?: string
+}
+
+function classNames(...classes: Array<string | false | null | undefined>) {
+  return classes.filter(Boolean).join(' ')
+}
+
+const defaultTimeline: FeedTimelineItem[] = [
+  {
+    id: 1,
+    content: 'Applied to',
+    target: 'Front End Developer',
+    href: '#',
+    date: 'Sep 20',
+    datetime: '2020-09-20',
+    icon: UserIcon,
+    iconBackground: 'bg-gray-400 dark:bg-gray-600',
+  },
+  {
+    id: 2,
+    content: 'Advanced to phone screening by',
+    target: 'Bethany Blake',
+    href: '#',
+    date: 'Sep 22',
+    datetime: '2020-09-22',
+    icon: HandThumbUpIcon,
+    iconBackground: 'bg-blue-500',
+  },
+  {
+    id: 3,
+    content: 'Completed phone screening with',
+    target: 'Martha Gardner',
+    href: '#',
+    date: 'Sep 28',
+    datetime: '2020-09-28',
+    icon: CheckIcon,
+    iconBackground: 'bg-green-500',
+  },
+  {
+    id: 4,
+    content: 'Advanced to interview by',
+    target: 'Bethany Blake',
+    href: '#',
+    date: 'Sep 30',
+    datetime: '2020-09-30',
+    icon: HandThumbUpIcon,
+    iconBackground: 'bg-blue-500',
+  },
+  {
+    id: 5,
+    content: 'Completed interview with',
+    target: 'Katherine Snyder',
+    href: '#',
+    date: 'Oct 4',
+    datetime: '2020-10-04',
+    icon: CheckIcon,
+    iconBackground: 'bg-green-500',
+  },
+]
+
+const defaultCommentActivity: FeedCommentActivityItem[] = [
+  {
+    id: 1,
+    type: 'created',
+    person: { name: 'Chelsea Hagon' },
+    date: '7d ago',
+    dateTime: '2023-01-23T10:32',
+  },
+  {
+    id: 2,
+    type: 'edited',
+    person: { name: 'Chelsea Hagon' },
+    date: '6d ago',
+    dateTime: '2023-01-23T11:03',
+  },
+  {
+    id: 3,
+    type: 'sent',
+    person: { name: 'Chelsea Hagon' },
+    date: '6d ago',
+    dateTime: '2023-01-23T11:24',
+  },
+  {
+    id: 4,
+    type: 'commented',
+    person: {
+      name: 'Chelsea Hagon',
+      imageUrl:
+        'https://images.unsplash.com/photo-1550525811-e5869dd03032?ixlib=rb-1.2.1&ixid=eyJhcHBfaWQiOjEyMDd9&auto=format&fit=facearea&facepad=2&w=256&h=256&q=80',
+    },
+    comment: 'Called client, they reassured me the invoice would be paid by the 25th.',
+    date: '3d ago',
+    dateTime: '2023-01-23T15:56',
+  },
+  {
+    id: 5,
+    type: 'viewed',
+    person: { name: 'Alex Curren' },
+    date: '2d ago',
+    dateTime: '2023-01-24T09:12',
+  },
+  {
+    id: 6,
+    type: 'paid',
+    person: { name: 'Alex Curren' },
+    date: '1d ago',
+    dateTime: '2023-01-24T09:20',
+  },
+]
+
+const defaultMultipleActivity: FeedMultipleActivityItem[] = [
+  {
+    id: 1,
+    type: 'comment',
+    person: { name: 'Eduardo Benz', href: '#' },
+    imageUrl:
+      'https://images.unsplash.com/photo-1520785643438-5bf77931f493?ixlib=rb-1.2.1&auto=format&fit=facearea&facepad=8&w=256&h=256&q=80',
+    comment:
+      'Lorem ipsum dolor sit amet, consectetur adipiscing elit. Tincidunt nunc ipsum tempor purus vitae id.',
+    date: '6d ago',
+  },
+  {
+    id: 2,
+    type: 'assignment',
+    person: { name: 'Hilary Mahy', href: '#' },
+    assigned: { name: 'Kristin Watson', href: '#' },
+    date: '2d ago',
+  },
+  {
+    id: 3,
+    type: 'tags',
+    person: { name: 'Hilary Mahy', href: '#' },
+    tags: [
+      { name: 'Bug', href: '#', color: 'fill-red-500' },
+      { name: 'Accessibility', href: '#', color: 'fill-indigo-500' },
+    ],
+    date: '6h ago',
+  },
+  {
+    id: 4,
+    type: 'comment',
+    person: { name: 'Jason Meyers', href: '#' },
+    imageUrl:
+      'https://images.unsplash.com/photo-1531427186611-ecfd6d936c79?ixlib=rb-1.2.1&auto=format&fit=facearea&facepad=8&w=256&h=256&q=80',
+    comment:
+      'Lorem ipsum dolor sit amet, consectetur adipiscing elit. Tincidunt nunc ipsum tempor purus vitae id.',
+    date: '2h ago',
+  },
+]
+
+const moods: Mood[] = [
+  { name: 'Excited', value: 'excited', icon: FireIcon, iconColor: 'text-white', bgColor: 'bg-red-500' },
+  { name: 'Loved', value: 'loved', icon: HeartIcon, iconColor: 'text-white', bgColor: 'bg-pink-400' },
+  { name: 'Happy', value: 'happy', icon: FaceSmileIcon, iconColor: 'text-white', bgColor: 'bg-green-400' },
+  { name: 'Sad', value: 'sad', icon: FaceFrownIcon, iconColor: 'text-white', bgColor: 'bg-yellow-400' },
+  { name: 'Thumbsy', value: 'thumbsy', icon: HandThumbUpIcon, iconColor: 'text-white', bgColor: 'bg-blue-500' },
+  {
+    name: 'I feel nothing',
+    value: null,
+    icon: XMarkIcon,
+    iconColor: 'text-gray-400 dark:text-gray-500',
+    bgColor: 'bg-transparent',
+  },
+]
+
+const defaultAvatar =
+  'https://images.unsplash.com/photo-1472099645785-5658abf4ff4e?ixlib=rb-1.2.1&ixid=eyJhcHBfaWQiOjEyMDd9&auto=format&fit=facearea&facepad=2&w=256&h=256&q=80'
+
+function FeedWithIcons({ timeline }: { timeline: FeedTimelineItem[] }) {
+  return (
+    <div className="flow-root">
+      <ul role="list" className="-mb-8">
+        {timeline.map((event, eventIndex) => (
+          <li key={event.id}>
+            <div className="relative pb-8">
+              {eventIndex !== timeline.length - 1 && (
+                <span
+                  aria-hidden="true"
+                  className="absolute top-4 left-4 -ml-px h-full w-0.5 bg-gray-200 dark:bg-white/10"
+                />
+              )}
+
+              <div className="relative flex space-x-3">
+                <div>
+                  <span
+                    className={classNames(
+                      event.iconBackground,
+                      'flex size-8 items-center justify-center rounded-full ring-8 ring-white dark:ring-gray-900',
+                    )}
+                  >
+                    <event.icon aria-hidden="true" className="size-5 text-white" />
+                  </span>
+                </div>
+
+                <div className="flex min-w-0 flex-1 justify-between space-x-4 pt-1.5">
+                  <div>
+                    <p className="text-sm text-gray-500 dark:text-gray-400">
+                      {event.content}{' '}
+                      <a href={event.href} className="font-medium text-gray-900 dark:text-white">
+                        {event.target}
+                      </a>
+                    </p>
+                  </div>
+
+                  <div className="text-right text-sm whitespace-nowrap text-gray-500 dark:text-gray-400">
+                    <time dateTime={event.datetime}>{event.date}</time>
+                  </div>
+                </div>
+              </div>
+            </div>
+          </li>
+        ))}
+      </ul>
+    </div>
+  )
+}
+
+function FeedWithComments({
+  activity,
+  currentUserAvatar,
+  showCommentForm,
+  onCommentSubmit,
+}: {
+  activity: FeedCommentActivityItem[]
+  currentUserAvatar: string
+  showCommentForm: boolean
+  onCommentSubmit?: (comment: string, mood: Mood) => void
+}) {
+  const [selectedMood, setSelectedMood] = useState(moods[5])
+
+  function handleSubmit(event: FormEvent<HTMLFormElement>) {
+    event.preventDefault()
+
+    const formData = new FormData(event.currentTarget)
+    const comment = String(formData.get('comment') ?? '').trim()
+
+    if (!comment) {
+      return
+    }
+
+    onCommentSubmit?.(comment, selectedMood)
+    event.currentTarget.reset()
+  }
+
+  return (
+    <>
+      <ul role="list" className="space-y-6">
+        {activity.map((activityItem, activityIndex) => (
+          <li key={activityItem.id} className="relative flex gap-x-4">
+            <div
+              className={classNames(
+                activityIndex === activity.length - 1 ? 'h-6' : '-bottom-6',
+                'absolute top-0 left-0 flex w-6 justify-center',
+              )}
+            >
+              <div className="w-px bg-gray-200 dark:bg-white/15" />
+            </div>
+
+            {activityItem.type === 'commented' ? (
+              <>
+                <img
+                  alt=""
+                  src={activityItem.person.imageUrl}
+                  className="relative mt-3 size-6 flex-none rounded-full bg-gray-50 outline -outline-offset-1 outline-black/5 dark:bg-gray-800 dark:outline-white/10"
+                />
+
+                <div className="flex-auto rounded-md p-3 ring-1 ring-gray-200 ring-inset dark:ring-white/15">
+                  <div className="flex justify-between gap-x-4">
+                    <div className="py-0.5 text-xs/5 text-gray-500 dark:text-gray-400">
+                      <span className="font-medium text-gray-900 dark:text-white">
+                        {activityItem.person.name}
+                      </span>{' '}
+                      commented
+                    </div>
+
+                    <time
+                      dateTime={activityItem.dateTime}
+                      className="flex-none py-0.5 text-xs/5 text-gray-500 dark:text-gray-400"
+                    >
+                      {activityItem.date}
+                    </time>
+                  </div>
+
+                  <p className="text-sm/6 text-gray-500 dark:text-gray-400">
+                    {activityItem.comment}
+                  </p>
+                </div>
+              </>
+            ) : (
+              <>
+                <div className="relative flex size-6 flex-none items-center justify-center bg-white dark:bg-gray-900">
+                  {activityItem.type === 'paid' ? (
+                    <CheckCircleIcon
+                      aria-hidden="true"
+                      className="size-6 text-indigo-600 dark:text-indigo-500"
+                    />
+                  ) : (
+                    <div className="size-1.5 rounded-full bg-gray-100 ring ring-gray-300 dark:bg-white/10 dark:ring-white/20" />
+                  )}
+                </div>
+
+                <p className="flex-auto py-0.5 text-xs/5 text-gray-500 dark:text-gray-400">
+                  <span className="font-medium text-gray-900 dark:text-white">
+                    {activityItem.person.name}
+                  </span>{' '}
+                  {activityItem.type} the invoice.
+                </p>
+
+                <time
+                  dateTime={activityItem.dateTime}
+                  className="flex-none py-0.5 text-xs/5 text-gray-500 dark:text-gray-400"
+                >
+                  {activityItem.date}
+                </time>
+              </>
+            )}
+          </li>
+        ))}
+      </ul>
+
+      {showCommentForm && (
+        <div className="mt-6 flex gap-x-3">
+          <img
+            alt=""
+            src={currentUserAvatar}
+            className="size-6 flex-none rounded-full bg-gray-50 outline -outline-offset-1 outline-black/5 dark:bg-gray-800 dark:outline-white/10"
+          />
+
+          <form onSubmit={handleSubmit} className="relative flex-auto">
+            <div className="overflow-hidden rounded-lg pb-12 outline-1 -outline-offset-1 outline-gray-300 focus-within:outline-2 focus-within:-outline-offset-2 focus-within:outline-indigo-600 dark:bg-white/5 dark:outline-white/10 dark:focus-within:outline-indigo-500">
+              <label htmlFor="comment" className="sr-only">
+                Kommentar hinzufügen
+              </label>
+
+              <textarea
+                id="comment"
+                name="comment"
+                rows={2}
+                placeholder="Kommentar hinzufügen..."
+                className="block w-full resize-none bg-transparent px-3 py-1.5 text-base text-gray-900 placeholder:text-gray-400 focus:outline-none sm:text-sm/6 dark:text-white dark:placeholder:text-gray-500"
+              />
+            </div>
+
+            <div className="absolute inset-x-0 bottom-0 flex justify-between py-2 pr-2 pl-3">
+              <div className="flex items-center space-x-5">
+                <button
+                  type="button"
+                  className="-m-2.5 flex size-10 items-center justify-center rounded-full text-gray-400 hover:text-gray-500 dark:text-gray-500 dark:hover:text-white"
+                >
+                  <PaperClipIcon aria-hidden="true" className="size-5" />
+                  <span className="sr-only">Datei anhängen</span>
+                </button>
+
+                <Listbox value={selectedMood} onChange={setSelectedMood}>
+                  <Label className="sr-only">Stimmung</Label>
+
+                  <div className="relative">
+                    <ListboxButton className="relative -m-2.5 flex size-10 items-center justify-center rounded-full text-gray-400 hover:text-gray-500 dark:text-gray-500 dark:hover:text-white">
+                      <span className="flex items-center justify-center">
+                        {selectedMood.value === null ? (
+                          <span>
+                            <FaceSmileIcon aria-hidden="true" className="size-5 shrink-0" />
+                            <span className="sr-only">Stimmung hinzufügen</span>
+                          </span>
+                        ) : (
+                          <span>
+                            <span
+                              className={classNames(
+                                selectedMood.bgColor,
+                                'flex size-8 items-center justify-center rounded-full',
+                              )}
+                            >
+                              <selectedMood.icon aria-hidden="true" className="size-5 shrink-0 text-white" />
+                            </span>
+                            <span className="sr-only">{selectedMood.name}</span>
+                          </span>
+                        )}
+                      </span>
+                    </ListboxButton>
+
+                    <ListboxOptions
+                      transition
+                      className="absolute bottom-10 z-10 -ml-6 w-60 rounded-lg bg-white py-3 text-base shadow-sm outline-1 outline-black/5 data-leave:transition data-leave:duration-100 data-leave:ease-in data-closed:data-leave:opacity-0 sm:ml-auto sm:w-64 sm:text-sm dark:bg-gray-800 dark:shadow-none dark:-outline-offset-1 dark:outline-white/10"
+                    >
+                      {moods.map((mood) => (
+                        <ListboxOption
+                          key={mood.value ?? 'none'}
+                          value={mood}
+                          className="relative cursor-default bg-white px-3 py-2 text-gray-900 select-none data-focus:bg-gray-100 dark:bg-transparent dark:text-white dark:data-focus:bg-white/5"
+                        >
+                          <div className="flex items-center">
+                            <div
+                              className={classNames(
+                                mood.bgColor,
+                                'flex size-8 items-center justify-center rounded-full',
+                              )}
+                            >
+                              <mood.icon
+                                aria-hidden="true"
+                                className={classNames(mood.iconColor, 'size-5 shrink-0')}
+                              />
+                            </div>
+
+                            <span className="ml-3 block truncate font-medium">
+                              {mood.name}
+                            </span>
+                          </div>
+                        </ListboxOption>
+                      ))}
+                    </ListboxOptions>
+                  </div>
+                </Listbox>
+              </div>
+
+              <Button type="submit" variant="secondary" size="sm">
+                Kommentieren
+              </Button>
+            </div>
+          </form>
+        </div>
+      )}
+    </>
+  )
+}
+
+function FeedWithMultipleTypes({ activity }: { activity: FeedMultipleActivityItem[] }) {
+  return (
+    <div className="flow-root">
+      <ul role="list" className="-mb-8">
+        {activity.map((activityItem, activityIndex) => (
+          <li key={activityItem.id}>
+            <div className="relative pb-8">
+              {activityIndex !== activity.length - 1 && (
+                <span
+                  aria-hidden="true"
+                  className="absolute top-5 left-5 -ml-px h-full w-0.5 bg-gray-200 dark:bg-white/10"
+                />
+              )}
+
+              <div className="relative flex items-start space-x-3">
+                {activityItem.type === 'comment' && (
+                  <>
+                    <div className="relative">
+                      <img
+                        alt=""
+                        src={activityItem.imageUrl}
+                        className="flex size-10 items-center justify-center rounded-full bg-gray-400 ring-8 ring-white outline -outline-offset-1 outline-black/5 dark:ring-gray-900 dark:outline-white/10"
+                      />
+
+                      <span className="absolute -right-1 -bottom-0.5 rounded-tl bg-white px-0.5 py-px dark:bg-gray-900">
+                        <ChatBubbleLeftEllipsisIcon aria-hidden="true" className="size-5 text-gray-400" />
+                      </span>
+                    </div>
+
+                    <div className="min-w-0 flex-1">
+                      <div>
+                        <div className="text-sm">
+                          <a href={activityItem.person.href} className="font-medium text-gray-900 dark:text-white">
+                            {activityItem.person.name}
+                          </a>
+                        </div>
+
+                        <p className="mt-0.5 text-sm text-gray-500 dark:text-gray-400">
+                          Commented {activityItem.date}
+                        </p>
+                      </div>
+
+                      <div className="mt-2 text-sm text-gray-700 dark:text-gray-200">
+                        <p>{activityItem.comment}</p>
+                      </div>
+                    </div>
+                  </>
+                )}
+
+                {activityItem.type === 'assignment' && (
+                  <>
+                    <div>
+                      <div className="relative px-1">
+                        <div className="flex size-8 items-center justify-center rounded-full bg-gray-100 ring-8 ring-white dark:bg-gray-800 dark:ring-gray-900">
+                          <UserCircleIcon aria-hidden="true" className="size-5 text-gray-500 dark:text-gray-400" />
+                        </div>
+                      </div>
+                    </div>
+
+                    <div className="min-w-0 flex-1 py-1.5">
+                      <div className="text-sm text-gray-500 dark:text-gray-400">
+                        <a href={activityItem.person.href} className="font-medium text-gray-900 dark:text-white">
+                          {activityItem.person.name}
+                        </a>{' '}
+                        assigned{' '}
+                        <a href={activityItem.assigned.href} className="font-medium text-gray-900 dark:text-white">
+                          {activityItem.assigned.name}
+                        </a>{' '}
+                        <span className="whitespace-nowrap">{activityItem.date}</span>
+                      </div>
+                    </div>
+                  </>
+                )}
+
+                {activityItem.type === 'tags' && (
+                  <>
+                    <div>
+                      <div className="relative px-1">
+                        <div className="flex size-8 items-center justify-center rounded-full bg-gray-100 ring-8 ring-white dark:bg-gray-800 dark:ring-gray-900">
+                          <TagIcon aria-hidden="true" className="size-5 text-gray-500 dark:text-gray-400" />
+                        </div>
+                      </div>
+                    </div>
+
+                    <div className="min-w-0 flex-1 py-0">
+                      <div className="text-sm/8 text-gray-500 dark:text-gray-400">
+                        <span className="mr-0.5">
+                          <a href={activityItem.person.href} className="font-medium text-gray-900 dark:text-white">
+                            {activityItem.person.name}
+                          </a>{' '}
+                          added tags
+                        </span>{' '}
+
+                        <span className="mr-0.5">
+                          {activityItem.tags.map((tag) => (
+                            <Fragment key={tag.name}>
+                              <a
+                                href={tag.href}
+                                className="inline-flex items-center gap-x-1.5 rounded-full px-2 py-1 text-xs font-medium text-gray-900 inset-ring inset-ring-gray-200 dark:bg-white/5 dark:text-gray-100 dark:inset-ring-white/10"
+                              >
+                                <svg viewBox="0 0 6 6" aria-hidden="true" className={classNames(tag.color, 'size-1.5')}>
+                                  <circle r={3} cx={3} cy={3} />
+                                </svg>
+                                {tag.name}
+                              </a>{' '}
+                            </Fragment>
+                          ))}
+                        </span>
+
+                        <span className="whitespace-nowrap">{activityItem.date}</span>
+                      </div>
+                    </div>
+                  </>
+                )}
+              </div>
+            </div>
+          </li>
+        ))}
+      </ul>
+    </div>
+  )
+}
+
+export default function Feed({
+  variant = 'icons',
+  timeline = defaultTimeline,
+  activity = defaultCommentActivity,
+  multipleActivity = defaultMultipleActivity,
+  currentUserAvatar = defaultAvatar,
+  showCommentForm = true,
+  onCommentSubmit,
+  className,
+}: FeedProps) {
+  return (
+    <div className={className}>
+      {variant === 'icons' && <FeedWithIcons timeline={timeline} />}
+
+      {variant === 'comments' && (
+        <FeedWithComments
+          activity={activity}
+          currentUserAvatar={currentUserAvatar}
+          showCommentForm={showCommentForm}
+          onCommentSubmit={onCommentSubmit}
+        />
+      )}
+
+      {variant === 'multiple' && <FeedWithMultipleTypes activity={multipleActivity} />}
+    </div>
+  )
+}

frontend/src/components/LoginForm.tsx

@@ -0,0 +1,144 @@
+// frontend\src\components\LoginForm.tsx
+
+import type { FormEvent } from 'react'
+import Button from './Button'
+import Card from './Card'
+
+type LoginFormProps = {
+  title?: string
+  submitText?: string
+  isSubmitting?: boolean
+  forgotPasswordHref?: string
+  registerHref?: string
+  googleHref?: string
+  githubHref?: string
+  onSubmit?: (event: FormEvent<HTMLFormElement>) => void
+}
+
+export default function LoginForm({
+  title = 'Sign in to your account',
+  submitText = 'Sign in',
+  isSubmitting = false,
+  forgotPasswordHref = '#',
+  onSubmit,
+}: LoginFormProps) {
+  return (
+    <div className="flex min-h-full flex-col justify-center py-12 sm:px-6 lg:px-8">
+      <div className="sm:mx-auto sm:w-full sm:max-w-md">
+        <img
+          alt="Your Company"
+          src="https://tailwindcss.com/plus-assets/img/logos/mark.svg?color=indigo&shade=600"
+          className="mx-auto h-10 w-auto dark:hidden"
+        />
+        <img
+          alt="Your Company"
+          src="https://tailwindcss.com/plus-assets/img/logos/mark.svg?color=indigo&shade=500"
+          className="mx-auto h-10 w-auto not-dark:hidden"
+        />
+
+        <h2 className="mt-6 text-center text-2xl/9 font-bold tracking-tight text-gray-900 dark:text-white">
+          {title}
+        </h2>
+      </div>
+
+      <div className="mt-10 sm:mx-auto sm:w-full sm:max-w-[480px]">
+        <Card variant="edge-to-edge-mobile">
+          <form action="#" method="POST" onSubmit={onSubmit} className="space-y-6">
+            <div>
+              <label htmlFor="identifier" className="block text-sm/6 font-medium text-gray-900 dark:text-white">
+                Benutzername oder E-Mail
+              </label>
+
+              <div className="mt-2">
+                <input
+                  id="identifier"
+                  name="identifier"
+                  type="text"
+                  required
+                  autoComplete="username"
+                  className="block w-full rounded-md bg-white px-3 py-1.5 text-base text-gray-900 outline-1 -outline-offset-1 outline-gray-300 placeholder:text-gray-400 focus:outline-2 focus:-outline-offset-2 focus:outline-indigo-600 sm:text-sm/6 dark:bg-white/5 dark:text-white dark:outline-white/10 dark:placeholder:text-gray-500 dark:focus:outline-indigo-500"
+                />
+              </div>
+            </div>
+
+            <div>
+              <label htmlFor="password" className="block text-sm/6 font-medium text-gray-900 dark:text-white">
+                Passwort
+              </label>
+
+              <div className="mt-2">
+                <input
+                  id="password"
+                  name="password"
+                  type="password"
+                  required
+                  autoComplete="current-password"
+                  className="block w-full rounded-md bg-white px-3 py-1.5 text-base text-gray-900 outline-1 -outline-offset-1 outline-gray-300 placeholder:text-gray-400 focus:outline-2 focus:-outline-offset-2 focus:outline-indigo-600 sm:text-sm/6 dark:bg-white/5 dark:text-white dark:outline-white/10 dark:placeholder:text-gray-500 dark:focus:outline-indigo-500"
+                />
+              </div>
+            </div>
+
+            <div className="flex items-center justify-between">
+              <div className="flex gap-3">
+                <div className="flex h-6 shrink-0 items-center">
+                  <div className="group grid size-4 grid-cols-1">
+                    <input
+                      id="remember-me"
+                      name="remember-me"
+                      type="checkbox"
+                      className="col-start-1 row-start-1 appearance-none rounded-sm border border-gray-300 bg-white checked:border-indigo-600 checked:bg-indigo-600 indeterminate:border-indigo-600 indeterminate:bg-indigo-600 focus-visible:outline-2 focus-visible:outline-offset-2 focus-visible:outline-indigo-600 disabled:border-gray-300 disabled:bg-gray-100 disabled:checked:bg-gray-100 dark:border-white/10 dark:bg-white/5 dark:checked:border-indigo-500 dark:checked:bg-indigo-500 dark:indeterminate:border-indigo-500 dark:indeterminate:bg-indigo-500 dark:focus-visible:outline-indigo-500 forced-colors:appearance-auto"
+                    />
+
+                    <svg
+                      fill="none"
+                      viewBox="0 0 14 14"
+                      className="pointer-events-none col-start-1 row-start-1 size-3.5 self-center justify-self-center stroke-white group-has-disabled:stroke-gray-950/25 dark:group-has-disabled:stroke-white/25"
+                    >
+                      <path
+                        d="M3 8L6 11L11 3.5"
+                        strokeWidth={2}
+                        strokeLinecap="round"
+                        strokeLinejoin="round"
+                        className="opacity-0 group-has-checked:opacity-100"
+                      />
+                      <path
+                        d="M3 7H11"
+                        strokeWidth={2}
+                        strokeLinecap="round"
+                        strokeLinejoin="round"
+                        className="opacity-0 group-has-indeterminate:opacity-100"
+                      />
+                    </svg>
+                  </div>
+                </div>
+
+                <label htmlFor="remember-me" className="block text-sm/6 text-gray-900 dark:text-white">
+                  Angemeldet bleiben
+                </label>
+              </div>
+
+              <div className="text-sm/6">
+                <a
+                  href={forgotPasswordHref}
+                  className="font-semibold text-indigo-600 hover:text-indigo-500 dark:text-indigo-400 dark:hover:text-indigo-300"
+                >
+                  Passwort vergessen?
+                </a>
+              </div>
+            </div>
+
+            <Button
+              type="submit"
+              color="indigo"
+              size="sm"
+              className="w-full"
+              isLoading={isSubmitting}
+            >
+              {submitText}
+            </Button>
+          </form>
+        </Card>
+      </div>
+    </div>
+  )
+}

frontend/src/components/Modal.tsx

@@ -0,0 +1,259 @@
+import { Dialog, DialogBackdrop, DialogPanel, DialogTitle } from '@headlessui/react'
+import {
+  CheckIcon,
+  ExclamationTriangleIcon,
+  XMarkIcon,
+} from '@heroicons/react/24/outline'
+
+type ModalVariant =
+  | 'success-single'
+  | 'success-wide'
+  | 'alert'
+  | 'alert-dismiss'
+  | 'alert-gray-footer'
+  | 'alert-left-buttons'
+
+type ModalProps = {
+  open: boolean
+  setOpen: (open: boolean) => void
+  variant?: ModalVariant
+  title?: string
+  description?: string
+  confirmText?: string
+  cancelText?: string
+  onConfirm?: () => void
+}
+
+function classNames(...classes: Array<string | false | null | undefined>) {
+  return classes.filter(Boolean).join(' ')
+}
+
+export default function Modal({
+  open,
+  setOpen,
+  variant = 'success-single',
+  title,
+  description,
+  confirmText,
+  cancelText = 'Cancel',
+  onConfirm,
+}: ModalProps) {
+  const isSuccess = variant === 'success-single' || variant === 'success-wide'
+  const isGrayFooter = variant === 'alert-gray-footer'
+  const isDismiss = variant === 'alert-dismiss'
+  const isLeftButtons = variant === 'alert-left-buttons'
+  const isWideSuccess = variant === 'success-wide'
+
+  const Icon = isSuccess ? CheckIcon : ExclamationTriangleIcon
+
+  const resolvedTitle =
+    title ?? (isSuccess ? 'Payment successful' : 'Deactivate account')
+
+  const resolvedDescription =
+    description ??
+    (isSuccess
+      ? 'Lorem ipsum dolor sit amet consectetur adipisicing elit. Consequatur amet labore.'
+      : 'Are you sure you want to deactivate your account? All of your data will be permanently removed from our servers forever. This action cannot be undone.')
+
+  const resolvedConfirmText =
+    confirmText ?? (isSuccess ? 'Go back to dashboard' : 'Deactivate')
+
+  function handleConfirm() {
+    onConfirm?.()
+    setOpen(false)
+  }
+
+  if (isGrayFooter) {
+    return (
+      <Dialog open={open} onClose={setOpen} className="relative z-10">
+        <DialogBackdrop
+          transition
+          className="fixed inset-0 bg-gray-500/75 transition-opacity data-closed:opacity-0 data-enter:duration-300 data-enter:ease-out data-leave:duration-200 data-leave:ease-in dark:bg-gray-900/50"
+        />
+
+        <div className="fixed inset-0 z-10 w-screen overflow-y-auto">
+          <div className="flex min-h-full items-end justify-center p-4 text-center sm:items-center sm:p-0">
+            <DialogPanel
+              transition
+              className="relative transform overflow-hidden rounded-lg bg-white text-left shadow-xl transition-all data-closed:translate-y-4 data-closed:opacity-0 data-enter:duration-300 data-enter:ease-out data-leave:duration-200 data-leave:ease-in sm:my-8 sm:w-full sm:max-w-lg data-closed:sm:translate-y-0 data-closed:sm:scale-95 dark:bg-gray-800 dark:outline dark:-outline-offset-1 dark:outline-white/10"
+            >
+              <div className="bg-white px-4 pt-5 pb-4 sm:p-6 sm:pb-4 dark:bg-gray-800">
+                <div className="sm:flex sm:items-start">
+                  <div className="mx-auto flex size-12 shrink-0 items-center justify-center rounded-full bg-red-100 sm:mx-0 sm:size-10 dark:bg-red-500/10">
+                    <Icon aria-hidden="true" className="size-6 text-red-600 dark:text-red-400" />
+                  </div>
+
+                  <div className="mt-3 text-center sm:mt-0 sm:ml-4 sm:text-left">
+                    <DialogTitle as="h3" className="text-base font-semibold text-gray-900 dark:text-white">
+                      {resolvedTitle}
+                    </DialogTitle>
+
+                    <div className="mt-2">
+                      <p className="text-sm text-gray-500 dark:text-gray-400">
+                        {resolvedDescription}
+                      </p>
+                    </div>
+                  </div>
+                </div>
+              </div>
+
+              <div className="bg-gray-50 px-4 py-3 sm:flex sm:flex-row-reverse sm:px-6 dark:bg-gray-700/25">
+                <button
+                  type="button"
+                  onClick={handleConfirm}
+                  className="inline-flex w-full justify-center rounded-md bg-red-600 px-3 py-2 text-sm font-semibold text-white shadow-xs hover:bg-red-500 sm:ml-3 sm:w-auto dark:bg-red-500 dark:shadow-none dark:hover:bg-red-400"
+                >
+                  {resolvedConfirmText}
+                </button>
+
+                <button
+                  type="button"
+                  data-autofocus
+                  onClick={() => setOpen(false)}
+                  className="mt-3 inline-flex w-full justify-center rounded-md bg-white px-3 py-2 text-sm font-semibold text-gray-900 shadow-xs inset-ring inset-ring-gray-300 hover:bg-gray-50 sm:mt-0 sm:w-auto dark:bg-white/10 dark:text-white dark:shadow-none dark:inset-ring-white/5 dark:hover:bg-white/20"
+                >
+                  {cancelText}
+                </button>
+              </div>
+            </DialogPanel>
+          </div>
+        </div>
+      </Dialog>
+    )
+  }
+
+  return (
+    <Dialog open={open} onClose={setOpen} className="relative z-10">
+      <DialogBackdrop
+        transition
+        className="fixed inset-0 bg-gray-500/75 transition-opacity data-closed:opacity-0 data-enter:duration-300 data-enter:ease-out data-leave:duration-200 data-leave:ease-in dark:bg-gray-900/50"
+      />
+
+      <div className="fixed inset-0 z-10 w-screen overflow-y-auto">
+        <div className="flex min-h-full items-end justify-center p-4 text-center sm:items-center sm:p-0">
+          <DialogPanel
+            transition
+            className={classNames(
+              'relative transform overflow-hidden rounded-lg bg-white px-4 pt-5 pb-4 text-left shadow-xl transition-all data-closed:translate-y-4 data-closed:opacity-0 data-enter:duration-300 data-enter:ease-out data-leave:duration-200 data-leave:ease-in sm:my-8 sm:w-full sm:p-6 data-closed:sm:translate-y-0 data-closed:sm:scale-95 dark:bg-gray-800 dark:outline dark:-outline-offset-1 dark:outline-white/10',
+              isSuccess && !isWideSuccess ? 'sm:max-w-sm' : 'sm:max-w-lg',
+            )}
+          >
+            {isDismiss && (
+              <div className="absolute top-0 right-0 hidden pt-4 pr-4 sm:block">
+                <button
+                  type="button"
+                  onClick={() => setOpen(false)}
+                  className="rounded-md bg-white text-gray-400 hover:text-gray-500 focus:outline-2 focus:outline-offset-2 focus:outline-indigo-600 dark:bg-gray-800 dark:hover:text-gray-300 dark:focus:outline-white"
+                >
+                  <span className="sr-only">Close</span>
+                  <XMarkIcon aria-hidden="true" className="size-6" />
+                </button>
+              </div>
+            )}
+
+            <div className={classNames(!isSuccess && 'sm:flex sm:items-start')}>
+              <div
+                className={classNames(
+                  'mx-auto flex size-12 shrink-0 items-center justify-center rounded-full',
+                  isSuccess
+                    ? 'bg-green-100 dark:bg-green-500/10'
+                    : 'bg-red-100 sm:mx-0 sm:size-10 dark:bg-red-500/10',
+                )}
+              >
+                <Icon
+                  aria-hidden="true"
+                  className={classNames(
+                    'size-6',
+                    isSuccess ? 'text-green-600 dark:text-green-400' : 'text-red-600 dark:text-red-400',
+                  )}
+                />
+              </div>
+
+              <div
+                className={classNames(
+                  'mt-3 text-center',
+                  isSuccess ? 'sm:mt-5' : 'sm:mt-0 sm:ml-4 sm:text-left',
+                )}
+              >
+                <DialogTitle as="h3" className="text-base font-semibold text-gray-900 dark:text-white">
+                  {resolvedTitle}
+                </DialogTitle>
+
+                <div className="mt-2">
+                  <p className="text-sm text-gray-500 dark:text-gray-400">
+                    {resolvedDescription}
+                  </p>
+                </div>
+              </div>
+            </div>
+
+            {variant === 'success-single' && (
+              <div className="mt-5 sm:mt-6">
+                <button
+                  type="button"
+                  onClick={handleConfirm}
+                  className="inline-flex w-full justify-center rounded-md bg-indigo-600 px-3 py-2 text-sm font-semibold text-white shadow-xs hover:bg-indigo-500 focus-visible:outline-2 focus-visible:outline-offset-2 focus-visible:outline-indigo-600 dark:bg-indigo-500 dark:shadow-none dark:hover:bg-indigo-400 dark:focus-visible:outline-indigo-500"
+                >
+                  {resolvedConfirmText}
+                </button>
+              </div>
+            )}
+
+            {variant === 'success-wide' && (
+              <div className="mt-5 sm:mt-6 sm:grid sm:grid-flow-row-dense sm:grid-cols-2 sm:gap-3">
+                <button
+                  type="button"
+                  onClick={handleConfirm}
+                  className="inline-flex w-full justify-center rounded-md bg-indigo-600 px-3 py-2 text-sm font-semibold text-white shadow-xs hover:bg-indigo-500 focus-visible:outline-2 focus-visible:outline-offset-2 focus-visible:outline-indigo-600 sm:col-start-2 dark:bg-indigo-500 dark:shadow-none dark:hover:bg-indigo-400 dark:focus-visible:outline-indigo-500"
+                >
+                  {resolvedConfirmText}
+                </button>
+
+                <button
+                  type="button"
+                  data-autofocus
+                  onClick={() => setOpen(false)}
+                  className="mt-3 inline-flex w-full justify-center rounded-md bg-white px-3 py-2 text-sm font-semibold text-gray-900 shadow-xs inset-ring-1 inset-ring-gray-300 hover:bg-gray-50 sm:col-start-1 sm:mt-0 dark:bg-white/10 dark:text-white dark:shadow-none dark:inset-ring-white/5 dark:hover:bg-white/20"
+                >
+                  {cancelText}
+                </button>
+              </div>
+            )}
+
+            {!isSuccess && (
+              <div
+                className={classNames(
+                  'mt-5 sm:mt-4',
+                  isLeftButtons ? 'sm:ml-10 sm:flex sm:pl-4' : 'sm:flex sm:flex-row-reverse',
+                )}
+              >
+                <button
+                  type="button"
+                  onClick={handleConfirm}
+                  className={classNames(
+                    'inline-flex w-full justify-center rounded-md bg-red-600 px-3 py-2 text-sm font-semibold text-white shadow-xs hover:bg-red-500 dark:bg-red-500 dark:shadow-none dark:hover:bg-red-400',
+                    isLeftButtons ? 'sm:w-auto' : 'sm:ml-3 sm:w-auto',
+                  )}
+                >
+                  {resolvedConfirmText}
+                </button>
+
+                <button
+                  type="button"
+                  data-autofocus
+                  onClick={() => setOpen(false)}
+                  className={classNames(
+                    'mt-3 inline-flex w-full justify-center rounded-md bg-white px-3 py-2 text-sm font-semibold text-gray-900 shadow-xs inset-ring-1 inset-ring-gray-300 hover:bg-gray-50 sm:mt-0 sm:w-auto dark:bg-white/10 dark:text-white dark:shadow-none dark:inset-ring-white/5 dark:hover:bg-white/20',
+                    isLeftButtons && 'sm:ml-3',
+                  )}
+                >
+                  {cancelText}
+                </button>
+              </div>
+            )}
+          </DialogPanel>
+        </div>
+      </div>
+    </Dialog>
+  )
+}

frontend/src/components/Search.tsx

@@ -0,0 +1,20 @@
+// frontend\src\components\Search.tsx
+
+import { MagnifyingGlassIcon } from '@heroicons/react/20/solid'
+
+export default function Search() {
+  return (
+    <form action="#" method="GET" className="grid flex-1 grid-cols-1">
+      <input
+        name="search"
+        placeholder="Search"
+        aria-label="Search"
+        className="col-start-1 row-start-1 block size-full bg-white pl-8 text-base text-gray-900 outline-hidden placeholder:text-gray-400 sm:text-sm/6 dark:bg-gray-900 dark:text-white dark:placeholder:text-gray-500"
+      />
+      <MagnifyingGlassIcon
+        aria-hidden="true"
+        className="pointer-events-none col-start-1 row-start-1 size-5 self-center text-gray-400"
+      />
+    </form>
+  )
+}

frontend/src/components/Sidebar.tsx

@@ -0,0 +1,206 @@
+// frontend\src\components\Sidebar.tsx
+
+import {
+  Dialog,
+  DialogBackdrop,
+  DialogPanel,
+  TransitionChild,
+} from '@headlessui/react'
+import {
+  CalendarIcon,
+  ChartPieIcon,
+  Cog6ToothIcon,
+  ComputerDesktopIcon,
+  DocumentDuplicateIcon,
+  FireIcon,
+  HomeIcon,
+  XMarkIcon,
+} from '@heroicons/react/24/outline'
+import { NavLink } from 'react-router'
+
+const navigation = [
+  { name: 'Dashboard', href: '/', icon: HomeIcon },
+  { name: 'Geräte', href: '/geraete', icon: ComputerDesktopIcon },
+  { name: 'Einsätze', href: '/einsaetze', icon: FireIcon },
+  { name: 'Kalender', href: '/kalender', icon: CalendarIcon },
+  { name: 'Dokumente', href: '/dokumente', icon: DocumentDuplicateIcon },
+  { name: 'Berichte', href: '/berichte', icon: ChartPieIcon },
+]
+
+type Team = {
+  id: string
+  name: string
+  initial: string
+  href: string
+  current: boolean
+}
+
+type User = {
+  id: string
+  username: string
+  displayName: string
+  email: string
+  avatar: string
+  unit: string
+  group: string
+  rights: string[]
+  teams: Team[]
+}
+
+type SidebarProps = {
+  user: User
+  sidebarOpen: boolean
+  setSidebarOpen: (open: boolean) => void
+}
+
+function classNames(...classes: Array<string | false | null | undefined>) {
+  return classes.filter(Boolean).join(' ')
+}
+
+function getTeamInitial(team: Team) {
+  if (team.initial) {
+    return team.initial
+  }
+
+  return team.name.charAt(0).toUpperCase()
+}
+
+function SidebarContent({
+  user,
+  setSidebarOpen,
+}: {
+  user: User
+  setSidebarOpen: (open: boolean) => void
+}) {
+  const teams = user.teams ?? []
+
+  return (
+    <>
+      <div className="flex h-16 shrink-0 items-center">
+        <img
+          alt="Your Company"
+          src="https://tailwindcss.com/plus-assets/img/logos/mark.svg?color=indigo&shade=500"
+          className="h-8 w-auto"
+        />
+      </div>
+
+      <nav className="flex flex-1 flex-col">
+        <ul role="list" className="flex flex-1 flex-col gap-y-7">
+          <li>
+            <ul role="list" className="-mx-2 space-y-1">
+              {navigation.map((item) => (
+                <li key={item.name}>
+                  <NavLink
+                    to={item.href}
+                    onClick={() => setSidebarOpen(false)}
+                    className={({ isActive }) =>
+                      classNames(
+                        isActive
+                          ? 'bg-white/5 text-white'
+                          : 'text-gray-400 hover:bg-white/5 hover:text-white',
+                        'group flex gap-x-3 rounded-md p-2 text-sm/6 font-semibold',
+                      )
+                    }
+                  >
+                    <item.icon aria-hidden="true" className="size-6 shrink-0" />
+                    {item.name}
+                  </NavLink>
+                </li>
+              ))}
+            </ul>
+          </li>
+
+          <li>
+            <div className="text-xs/6 font-semibold text-gray-400">
+              Zugeordnete Teams
+            </div>
+
+            <ul role="list" className="-mx-2 mt-2 space-y-1">
+              {teams.length > 0 ? (
+                teams.map((team) => (
+                  <li key={team.id}>
+                    <a
+                      href={team.href || '#'}
+                      className={classNames(
+                        team.current
+                          ? 'bg-white/5 text-white'
+                          : 'text-gray-400 hover:bg-white/5 hover:text-white',
+                        'group flex gap-x-3 rounded-md p-2 text-sm/6 font-semibold',
+                      )}
+                    >
+                      <span className="flex size-6 shrink-0 items-center justify-center rounded-lg border border-white/10 bg-white/5 text-[0.625rem] font-medium text-gray-400 group-hover:border-white/20 group-hover:text-white">
+                        {getTeamInitial(team)}
+                      </span>
+                      <span className="truncate">{team.name}</span>
+                    </a>
+                  </li>
+                ))
+              ) : (
+                <li className="px-2 py-1 text-sm/6 text-gray-500">
+                  Keine Teams zugeordnet
+                </li>
+              )}
+            </ul>
+          </li>
+
+          <li className="mt-auto">
+            <NavLink
+              to="/einstellungen"
+              onClick={() => setSidebarOpen(false)}
+              className={({ isActive }) =>
+                classNames(
+                  isActive
+                    ? 'bg-white/5 text-white'
+                    : 'text-gray-400 hover:bg-white/5 hover:text-white',
+                  'group -mx-2 flex gap-x-3 rounded-md p-2 text-sm/6 font-semibold',
+                )
+              }
+            >
+              <Cog6ToothIcon aria-hidden="true" className="size-6 shrink-0" />
+              Einstellungen
+            </NavLink>
+          </li>
+        </ul>
+      </nav>
+    </>
+  )
+}
+
+export default function Sidebar({ user, sidebarOpen, setSidebarOpen }: SidebarProps) {
+  return (
+    <>
+      <Dialog open={sidebarOpen} onClose={setSidebarOpen} className="relative z-50 lg:hidden">
+        <DialogBackdrop
+          transition
+          className="fixed inset-0 bg-gray-900/80 transition-opacity duration-300 ease-linear data-closed:opacity-0"
+        />
+
+        <div className="fixed inset-0 flex">
+          <DialogPanel
+            transition
+            className="relative mr-16 flex w-full max-w-xs flex-1 transform transition duration-300 ease-in-out data-closed:-translate-x-full"
+          >
+            <TransitionChild>
+              <div className="absolute top-0 left-full flex w-16 justify-center pt-5 duration-300 ease-in-out data-closed:opacity-0">
+                <button type="button" onClick={() => setSidebarOpen(false)} className="-m-2.5 p-2.5">
+                  <span className="sr-only">Close sidebar</span>
+                  <XMarkIcon aria-hidden="true" className="size-6 text-white" />
+                </button>
+              </div>
+            </TransitionChild>
+
+            <div className="relative flex grow flex-col gap-y-5 overflow-y-auto bg-gray-900 px-6 pb-4 ring-1 ring-white/10 dark:before:pointer-events-none dark:before:absolute dark:before:inset-0 dark:before:bg-black/10">
+              <SidebarContent user={user} setSidebarOpen={setSidebarOpen} />
+            </div>
+          </DialogPanel>
+        </div>
+      </Dialog>
+
+      <div className="hidden bg-gray-900 ring-1 ring-white/10 lg:fixed lg:inset-y-0 lg:z-50 lg:flex lg:w-72 lg:flex-col">
+        <div className="flex grow flex-col gap-y-5 overflow-y-auto bg-black/10 px-6 pb-4">
+          <SidebarContent user={user} setSidebarOpen={setSidebarOpen} />
+        </div>
+      </div>
+    </>
+  )
+}

frontend/src/components/Tables.tsx

@@ -0,0 +1,673 @@
+// frontend/src/components/Tables.tsx
+
+import {
+  Fragment,
+  type ReactNode,
+  useLayoutEffect,
+  useRef,
+  useState,
+} from 'react'
+import { ChevronDownIcon } from '@heroicons/react/20/solid'
+import Button from './Button'
+
+export type TableVariant =
+  | 'simple'
+  | 'card'
+  | 'full-width'
+  | 'constrained'
+  | 'striped'
+  | 'uppercase'
+  | 'stacked-mobile'
+  | 'hidden-mobile'
+  | 'avatars'
+  | 'sticky-header'
+  | 'vertical-lines'
+  | 'condensed'
+  | 'sortable'
+  | 'grouped'
+  | 'summary'
+  | 'border'
+
+export type TableColumn<T> = {
+  key: string
+  header: string
+  render: (row: T) => ReactNode
+  mobileRender?: (row: T) => ReactNode
+  isPrimary?: boolean
+  sortable?: boolean
+  hideOnMobile?: 'sm' | 'md' | 'lg'
+  align?: 'left' | 'center' | 'right'
+  className?: string
+  headerClassName?: string
+}
+
+export type TableGroup<T> = {
+  id: string | number
+  name: string
+  rows: T[]
+}
+
+export type TableSummaryRow = {
+  label: ReactNode
+  value: ReactNode
+  emphasized?: boolean
+  colSpan?: number
+}
+
+type SortDirection = 'asc' | 'desc'
+
+type TablesProps<T> = {
+  title?: string
+  description?: string
+
+  rows?: T[]
+  groups?: TableGroup<T>[]
+
+  columns: TableColumn<T>[]
+  getRowId: (row: T) => string | number
+
+  variant?: TableVariant
+  emptyText?: string
+
+  actionLabel?: string
+  onAction?: () => void
+  headerAction?: ReactNode
+
+  rowActions?: (row: T) => ReactNode
+
+  selectable?: boolean
+  selectedRowIds?: Array<string | number>
+  onSelectedRowIdsChange?: (ids: Array<string | number>) => void
+
+  sortKey?: string
+  sortDirection?: SortDirection
+  onSort?: (column: TableColumn<T>) => void
+
+  summaryRows?: TableSummaryRow[]
+
+  hideHeadings?: boolean
+  stickyTopClassName?: string
+
+  className?: string
+}
+
+function classNames(...classes: Array<string | false | null | undefined>) {
+  return classes.filter(Boolean).join(' ')
+}
+
+function getAlignmentClass(align?: TableColumn<unknown>['align']) {
+  if (align === 'right') {
+    return 'text-right'
+  }
+
+  if (align === 'center') {
+    return 'text-center'
+  }
+
+  return 'text-left'
+}
+
+function getHiddenClass(hideOnMobile?: TableColumn<unknown>['hideOnMobile']) {
+  if (hideOnMobile === 'sm') {
+    return 'hidden sm:table-cell'
+  }
+
+  if (hideOnMobile === 'md') {
+    return 'hidden md:table-cell'
+  }
+
+  if (hideOnMobile === 'lg') {
+    return 'hidden lg:table-cell'
+  }
+
+  return ''
+}
+
+function Checkbox({
+  checked,
+  onChange,
+  inputRef,
+  value,
+}: {
+  checked: boolean
+  onChange: (checked: boolean) => void
+  inputRef?: React.Ref<HTMLInputElement>
+  value?: string
+}) {
+  return (
+    <div className="group absolute top-1/2 left-4 -mt-2 grid size-4 grid-cols-1">
+      <input
+        ref={inputRef}
+        type="checkbox"
+        value={value}
+        checked={checked}
+        onChange={(event) => onChange(event.target.checked)}
+        className="col-start-1 row-start-1 appearance-none rounded-sm border border-gray-300 bg-white checked:border-indigo-600 checked:bg-indigo-600 indeterminate:border-indigo-600 indeterminate:bg-indigo-600 focus-visible:outline-2 focus-visible:outline-offset-2 focus-visible:outline-indigo-600 disabled:border-gray-300 disabled:bg-gray-100 disabled:checked:bg-gray-100 dark:border-white/20 dark:bg-gray-800/50 dark:checked:border-indigo-500 dark:checked:bg-indigo-500 dark:indeterminate:border-indigo-500 dark:indeterminate:bg-indigo-500 dark:focus-visible:outline-indigo-500 dark:disabled:border-white/10 dark:disabled:bg-gray-800 dark:disabled:checked:bg-gray-800 forced-colors:appearance-auto"
+      />
+
+      <svg
+        viewBox="0 0 14 14"
+        fill="none"
+        className="pointer-events-none col-start-1 row-start-1 size-3.5 self-center justify-self-center stroke-white group-has-disabled:stroke-gray-950/25 dark:group-has-disabled:stroke-white/25"
+      >
+        <path
+          d="M3 8L6 11L11 3.5"
+          strokeWidth={2}
+          strokeLinecap="round"
+          strokeLinejoin="round"
+          className="opacity-0 group-has-checked:opacity-100"
+        />
+        <path
+          d="M3 7H11"
+          strokeWidth={2}
+          strokeLinecap="round"
+          strokeLinejoin="round"
+          className="opacity-0 group-has-indeterminate:opacity-100"
+        />
+      </svg>
+    </div>
+  )
+}
+
+export default function Tables<T>({
+  title,
+  description,
+
+  rows = [],
+  groups,
+
+  columns,
+  getRowId,
+
+  variant = 'simple',
+  emptyText = 'Keine Einträge vorhanden.',
+
+  actionLabel,
+  onAction,
+  headerAction,
+
+  rowActions,
+
+  selectable = false,
+  selectedRowIds,
+  onSelectedRowIdsChange,
+
+  sortKey,
+  sortDirection = 'asc',
+  onSort,
+
+  summaryRows,
+
+  hideHeadings = false,
+  stickyTopClassName = 'top-0',
+
+  className,
+}: TablesProps<T>) {
+  const headerCheckboxRef = useRef<HTMLInputElement>(null)
+  const [internalSelectedRowIds, setInternalSelectedRowIds] = useState<Array<string | number>>([])
+
+  const rowGroups =
+    groups && groups.length > 0
+      ? groups
+      : [
+          {
+            id: 'default',
+            name: '',
+            rows,
+          },
+        ]
+
+  const allRows = rowGroups.flatMap((group) => group.rows)
+  const allRowIds = allRows.map(getRowId)
+
+  const selectedIds = selectedRowIds ?? internalSelectedRowIds
+  const selectedSet = new Set(selectedIds)
+
+  const checked = allRowIds.length > 0 && selectedIds.length === allRowIds.length
+  const indeterminate = selectedIds.length > 0 && selectedIds.length < allRowIds.length
+
+  const isCard = variant === 'card'
+  const isBorder = variant === 'border'
+  const isFullWidth = variant === 'full-width'
+  const isConstrained = variant === 'constrained'
+  const isStriped = variant === 'striped'
+  const isUppercase = variant === 'uppercase'
+  const isStackedMobile = variant === 'stacked-mobile'
+  const isStickyHeader = variant === 'sticky-header'
+  const isVerticalLines = variant === 'vertical-lines'
+  const isCondensed = variant === 'condensed'
+  const isSortable = variant === 'sortable'
+  const isGrouped = variant === 'grouped' || Boolean(groups?.length)
+  const hasSummary = variant === 'summary' || Boolean(summaryRows?.length)
+
+  const totalColumns =
+    columns.length +
+    (selectable ? 1 : 0) +
+    (rowActions ? 1 : 0)
+
+  useLayoutEffect(() => {
+    if (!headerCheckboxRef.current) {
+      return
+    }
+
+    headerCheckboxRef.current.indeterminate = indeterminate
+  }, [indeterminate])
+
+  function updateSelected(nextSelectedIds: Array<string | number>) {
+    if (!selectedRowIds) {
+      setInternalSelectedRowIds(nextSelectedIds)
+    }
+
+    onSelectedRowIdsChange?.(nextSelectedIds)
+  }
+
+  function toggleAll(nextChecked: boolean) {
+    updateSelected(nextChecked ? allRowIds : [])
+  }
+
+  function toggleRow(rowId: string | number, nextChecked: boolean) {
+    if (nextChecked) {
+      updateSelected(Array.from(new Set([...selectedIds, rowId])))
+      return
+    }
+
+    updateSelected(selectedIds.filter((id) => id !== rowId))
+  }
+
+  function renderHeaderAction() {
+    if (headerAction) {
+      return headerAction
+    }
+
+    if (!actionLabel) {
+      return null
+    }
+
+    return (
+      <Button
+        type="button"
+        color="indigo"
+        size="md"
+        onClick={onAction}
+      >
+        {actionLabel}
+      </Button>
+    )
+  }
+
+  function renderHeader() {
+    if (!title && !description && !actionLabel && !headerAction) {
+      return null
+    }
+
+    return (
+      <div
+        className={classNames(
+          isConstrained && 'mx-auto max-w-7xl',
+          !isFullWidth && 'px-4 sm:px-6 lg:px-8',
+          isFullWidth && 'px-4 sm:px-6 lg:px-8',
+          'sm:flex sm:items-center',
+        )}
+      >
+        <div className="sm:flex-auto">
+          {title && (
+            <h1 className="text-base font-semibold text-gray-900 dark:text-white">
+              {title}
+            </h1>
+          )}
+
+          {description && (
+            <p className="mt-2 text-sm text-gray-700 dark:text-gray-300">
+              {description}
+            </p>
+          )}
+        </div>
+
+        {(actionLabel || headerAction) && (
+          <div className="mt-4 sm:mt-0 sm:ml-16 sm:flex-none">
+            {renderHeaderAction()}
+          </div>
+        )}
+      </div>
+    )
+  }
+
+  function renderColumnHeader(column: TableColumn<T>) {
+    const activeSortColumn = sortKey === column.key
+    const showSortIcon = isSortable || column.sortable
+
+    if (!showSortIcon) {
+      return column.header
+    }
+
+    return (
+      <button
+        type="button"
+        onClick={() => onSort?.(column)}
+        className="group inline-flex"
+      >
+        {column.header}
+
+        <span
+          className={classNames(
+            activeSortColumn
+              ? 'ml-2 flex-none rounded-sm bg-gray-100 text-gray-900 group-hover:bg-gray-200 dark:bg-gray-800 dark:text-white dark:group-hover:bg-gray-700'
+              : 'invisible ml-2 flex-none rounded-sm text-gray-400 group-hover:visible group-focus:visible dark:text-gray-500',
+          )}
+        >
+          <ChevronDownIcon
+            aria-hidden="true"
+            className={classNames(
+              'size-5',
+              activeSortColumn && sortDirection === 'asc' && 'rotate-180',
+            )}
+          />
+        </span>
+      </button>
+    )
+  }
+
+  function renderTableHead() {
+    return (
+      <thead
+        className={classNames(
+          hideHeadings && 'sr-only',
+          isCard && 'bg-gray-50 dark:bg-gray-800/75',
+          !isCard && 'bg-white dark:bg-gray-900',
+        )}
+      >
+        <tr className={classNames(isVerticalLines && 'divide-x divide-gray-200 dark:divide-white/10')}>
+          {selectable && (
+            <th scope="col" className="relative px-7 sm:w-12 sm:px-6">
+              <Checkbox
+                inputRef={headerCheckboxRef}
+                checked={checked}
+                onChange={toggleAll}
+              />
+            </th>
+          )}
+
+          {columns.map((column, columnIndex) => {
+            const isFirst = columnIndex === 0
+            const isLast = columnIndex === columns.length - 1 && !rowActions
+            const hiddenClass = getHiddenClass(column.hideOnMobile)
+
+            return (
+              <th
+                key={column.key}
+                scope="col"
+                className={classNames(
+                  isStickyHeader &&
+                    `sticky ${stickyTopClassName} z-10 bg-white/75 backdrop-blur-sm backdrop-filter dark:bg-gray-900/75`,
+                  isUppercase
+                    ? 'py-3 text-xs font-medium tracking-wide text-gray-500 uppercase dark:text-gray-400'
+                    : 'py-3.5 text-sm font-semibold text-gray-900 dark:text-white',
+                  isCondensed ? 'px-2' : 'px-3',
+                  isFirst && !selectable && 'pl-4 sm:pl-0',
+                  isCard && isFirst && 'sm:pl-6',
+                  isLast && !isCard && 'pr-4 sm:pr-0',
+                  isLast && isCard && 'sm:pr-6',
+                  getAlignmentClass(column.align),
+                  hiddenClass,
+                  column.headerClassName,
+                )}
+              >
+                {renderColumnHeader(column)}
+              </th>
+            )
+          })}
+
+          {rowActions && (
+            <th
+              scope="col"
+              className={classNames(
+                isStickyHeader &&
+                  `sticky ${stickyTopClassName} z-10 bg-white/75 backdrop-blur-sm backdrop-filter dark:bg-gray-900/75`,
+                'py-3.5 pr-4 pl-3 sm:pr-0',
+                isCard && 'sm:pr-6',
+              )}
+            >
+              <span className="sr-only">Aktionen</span>
+            </th>
+          )}
+        </tr>
+      </thead>
+    )
+  }
+
+  function renderRow(row: T, rowIndex: number) {
+    const rowId = getRowId(row)
+    const selected = selectedSet.has(rowId)
+
+    return (
+      <tr
+        key={rowId}
+        className={classNames(
+          isStriped && 'even:bg-gray-50 dark:even:bg-gray-800/50',
+          selected && 'bg-gray-50 dark:bg-gray-800/50',
+          isVerticalLines && 'divide-x divide-gray-200 dark:divide-white/10',
+        )}
+      >
+        {selectable && (
+          <td className="relative px-7 sm:w-12 sm:px-6">
+            {selected && (
+              <div className="absolute inset-y-0 left-0 w-0.5 bg-indigo-600 dark:bg-indigo-500" />
+            )}
+
+            <Checkbox
+              checked={selected}
+              value={String(rowId)}
+              onChange={(nextChecked) => toggleRow(rowId, nextChecked)}
+            />
+          </td>
+        )}
+
+        {columns.map((column, columnIndex) => {
+          const isFirst = columnIndex === 0
+          const isLast = columnIndex === columns.length - 1 && !rowActions
+          const hiddenClass = getHiddenClass(column.hideOnMobile)
+
+          return (
+            <td
+              key={column.key}
+              className={classNames(
+                isCondensed ? 'py-2' : isAvatarVariant(variant) ? 'py-5' : 'py-4',
+                isCondensed ? 'px-2' : 'px-3',
+                isFirst && !selectable && 'pl-4 sm:pl-0',
+                isCard && isFirst && 'sm:pl-6',
+                isLast && !isCard && 'pr-4 sm:pr-0',
+                isLast && isCard && 'sm:pr-6',
+                'text-sm text-gray-500 dark:text-gray-400',
+                !isStackedMobile && 'whitespace-nowrap',
+                column.isPrimary && 'font-medium text-gray-900 dark:text-white',
+                selected && column.isPrimary && 'text-indigo-600 dark:text-indigo-400',
+                getAlignmentClass(column.align),
+                hiddenClass,
+                column.className,
+              )}
+            >
+              {column.render(row)}
+
+              {isStackedMobile && column.isPrimary && column.mobileRender && (
+                <dl className="font-normal lg:hidden">
+                  {column.mobileRender(row)}
+                </dl>
+              )}
+            </td>
+          )
+        })}
+
+        {rowActions && (
+          <td
+            className={classNames(
+              isCondensed ? 'py-2' : 'py-4',
+              'pr-4 pl-3 text-right text-sm font-medium whitespace-nowrap sm:pr-0',
+              isCard && 'sm:pr-6',
+            )}
+          >
+            {rowActions(row)}
+          </td>
+        )}
+      </tr>
+    )
+  }
+
+  function renderGroupedRows() {
+    return rowGroups.map((group) => (
+      <Fragment key={group.id}>
+        {isGrouped && group.name && (
+          <tr className="border-t border-gray-200 dark:border-white/10">
+            <th
+              scope="colgroup"
+              colSpan={totalColumns}
+              className="bg-gray-50 py-2 pr-3 pl-4 text-left text-sm font-semibold text-gray-900 sm:pl-3 dark:bg-gray-800/50 dark:text-white"
+            >
+              {group.name}
+            </th>
+          </tr>
+        )}
+
+        {group.rows.map(renderRow)}
+      </Fragment>
+    ))
+  }
+
+  function renderEmptyRow() {
+    if (allRows.length > 0) {
+      return null
+    }
+
+    return (
+      <tr>
+        <td
+          colSpan={totalColumns}
+          className="px-4 py-10 text-center text-sm text-gray-500 dark:text-gray-400"
+        >
+          {emptyText}
+        </td>
+      </tr>
+    )
+  }
+
+  function renderSummaryRows() {
+    if (!hasSummary || !summaryRows?.length) {
+      return null
+    }
+
+    return (
+      <tfoot>
+        {summaryRows.map((row, index) => {
+          const colSpan = row.colSpan ?? Math.max(totalColumns - 1, 1)
+
+          return (
+            <tr key={index}>
+              <th
+                scope="row"
+                colSpan={colSpan}
+                className={classNames(
+                  index === 0 ? 'pt-6' : 'pt-4',
+                  'pr-3 pl-4 text-right text-sm sm:pl-0',
+                  row.emphasized
+                    ? 'font-semibold text-gray-900 dark:text-white'
+                    : 'font-normal text-gray-500 dark:text-gray-400',
+                )}
+              >
+                {row.label}
+              </th>
+
+              <td
+                className={classNames(
+                  index === 0 ? 'pt-6' : 'pt-4',
+                  'pr-4 pl-3 text-right text-sm sm:pr-0',
+                  row.emphasized
+                    ? 'font-semibold text-gray-900 dark:text-white'
+                    : 'text-gray-500 dark:text-gray-400',
+                )}
+              >
+                {row.value}
+              </td>
+            </tr>
+          )
+        })}
+      </tfoot>
+    )
+  }
+
+  function renderTable() {
+    return (
+      <table
+        className={classNames(
+          isStickyHeader
+            ? 'min-w-full border-separate border-spacing-0'
+            : 'relative min-w-full divide-y divide-gray-300 dark:divide-white/15',
+          isBorder && 'divide-y divide-gray-300 dark:divide-white/15',
+        )}
+      >
+        {renderTableHead()}
+
+        <tbody
+          className={classNames(
+            !isStickyHeader && 'divide-y divide-gray-200 dark:divide-white/10',
+            isCard
+              ? 'bg-white dark:bg-gray-800/50'
+              : 'bg-white dark:bg-gray-900',
+          )}
+        >
+          {renderEmptyRow()}
+          {renderGroupedRows()}
+        </tbody>
+
+        {renderSummaryRows()}
+      </table>
+    )
+  }
+
+  return (
+    <div className={className}>
+      {renderHeader()}
+
+      <div
+        className={classNames(
+          title || description || actionLabel || headerAction ? 'mt-8' : '',
+          'flow-root',
+          isFullWidth && 'overflow-hidden',
+        )}
+      >
+        <div
+          className={classNames(
+            isConstrained && 'mx-auto max-w-7xl px-4 sm:px-6 lg:px-8',
+            !isConstrained && '-mx-4 -my-2 overflow-x-auto sm:-mx-6 lg:-mx-8',
+          )}
+        >
+          <div
+            className={classNames(
+              isConstrained
+                ? ''
+                : 'inline-block min-w-full py-2 align-middle sm:px-6 lg:px-8',
+              isFullWidth && 'sm:px-0 lg:px-0',
+            )}
+          >
+            {isCard || isBorder ? (
+              <div
+                className={classNames(
+                  isCard &&
+                    'overflow-hidden shadow-sm outline-1 outline-black/5 sm:rounded-lg dark:shadow-none dark:-outline-offset-1 dark:outline-white/10',
+                  isBorder &&
+                    'overflow-hidden ring-1 ring-gray-300 sm:rounded-lg dark:ring-white/15',
+                )}
+              >
+                {renderTable()}
+              </div>
+            ) : (
+              renderTable()
+            )}
+          </div>
+        </div>
+      </div>
+    </div>
+  )
+}
+
+function isAvatarVariant(variant: TableVariant) {
+  return variant === 'avatars'
+}

frontend/src/components/Tabs.tsx

@@ -0,0 +1,398 @@
+// frontend\src\components\Tabs.tsx
+
+import type { ComponentType, SVGProps } from 'react'
+import { Link, useLocation, useNavigate } from 'react-router'
+import { ChevronDownIcon } from '@heroicons/react/16/solid'
+
+type TabIcon = ComponentType<SVGProps<SVGSVGElement>>
+
+export type TabItem = {
+  name: string
+  href: string
+  current?: boolean
+  icon?: TabIcon
+  count?: string | number
+}
+
+type TabsVariant =
+  | 'underline'
+  | 'underline-icons'
+  | 'pills'
+  | 'pills-gray'
+  | 'pills-brand'
+  | 'full-width-underline'
+  | 'bar-underline'
+  | 'underline-badges'
+  | 'simple'
+
+type TabsAlign = 'left' | 'center' | 'right'
+
+type TabsProps = {
+  tabs: TabItem[]
+  variant?: TabsVariant
+  align?: TabsAlign
+  sticky?: boolean
+  stickyTopClassName?: string
+  ariaLabel?: string
+  className?: string
+}
+
+function classNames(...classes: Array<string | false | null | undefined>) {
+  return classes.filter(Boolean).join(' ')
+}
+
+const alignClassMap: Record<TabsAlign, string> = {
+  left: 'justify-start',
+  center: 'justify-center',
+  right: 'justify-end',
+}
+
+function isTabActive(tab: TabItem, pathname: string) {
+  if (typeof tab.current === 'boolean') {
+    return tab.current
+  }
+
+  if (tab.href === '/') {
+    return pathname === '/'
+  }
+
+  return pathname.startsWith(tab.href)
+}
+
+export default function Tabs({
+  tabs,
+  variant = 'underline',
+  align = 'left',
+  sticky = false,
+  stickyTopClassName = 'top-16',
+  ariaLabel = 'Tabs',
+  className,
+}: TabsProps) {
+  const location = useLocation()
+  const navigate = useNavigate()
+
+  const activeTab = tabs.find((tab) => isTabActive(tab, location.pathname)) ?? tabs[0]
+  const alignClassName = alignClassMap[align]
+
+  function handleSelectChange(event: React.ChangeEvent<HTMLSelectElement>) {
+    const selectedTab = tabs.find((tab) => tab.name === event.target.value)
+
+    if (!selectedTab) {
+      return
+    }
+
+    if (selectedTab.href === '#') {
+      return
+    }
+
+    navigate(selectedTab.href)
+  }
+
+  return (
+    <div
+      className={classNames(
+        sticky && 'sticky z-30 bg-white dark:bg-gray-900',
+        sticky && stickyTopClassName,
+        className,
+      )}
+    >
+      <div className="grid grid-cols-1 sm:hidden">
+        <select
+          value={activeTab?.name}
+          onChange={handleSelectChange}
+          aria-label="Tab auswählen"
+          className="col-start-1 row-start-1 w-full appearance-none rounded-md bg-white py-2 pr-8 pl-3 text-base text-gray-900 outline-1 -outline-offset-1 outline-gray-300 focus:outline-2 focus:-outline-offset-2 focus:outline-indigo-600 dark:bg-white/5 dark:text-gray-100 dark:outline-white/10 dark:*:bg-gray-800 dark:focus:outline-indigo-500"
+        >
+          {tabs.map((tab) => (
+            <option key={tab.name}>{tab.name}</option>
+          ))}
+        </select>
+
+        <ChevronDownIcon
+          aria-hidden="true"
+          className="pointer-events-none col-start-1 row-start-1 mr-2 size-5 self-center justify-self-end fill-gray-500 dark:fill-gray-400"
+        />
+      </div>
+
+      <div className="hidden sm:block">
+        {variant === 'underline' && (
+          <div className="border-b border-gray-200 dark:border-white/10">
+            <nav aria-label={ariaLabel} className={classNames('-mb-px flex space-x-8', alignClassName)}>
+              {tabs.map((tab) => {
+                const active = isTabActive(tab, location.pathname)
+
+                return (
+                  <Link
+                    key={tab.name}
+                    to={tab.href}
+                    aria-current={active ? 'page' : undefined}
+                    className={classNames(
+                      active
+                        ? 'border-indigo-500 text-indigo-600 dark:border-indigo-400 dark:text-indigo-400'
+                        : 'border-transparent text-gray-500 hover:border-gray-300 hover:text-gray-700 dark:text-gray-400 dark:hover:border-white/20 dark:hover:text-gray-200',
+                      'border-b-2 px-1 py-4 text-sm font-medium whitespace-nowrap',
+                    )}
+                  >
+                    {tab.name}
+                  </Link>
+                )
+              })}
+            </nav>
+          </div>
+        )}
+
+        {variant === 'underline-icons' && (
+          <div className="border-b border-gray-200 dark:border-white/10">
+            <nav aria-label={ariaLabel} className={classNames('-mb-px flex space-x-8', alignClassName)}>
+              {tabs.map((tab) => {
+                const active = isTabActive(tab, location.pathname)
+                const Icon = tab.icon
+
+                return (
+                  <Link
+                    key={tab.name}
+                    to={tab.href}
+                    aria-current={active ? 'page' : undefined}
+                    className={classNames(
+                      active
+                        ? 'border-indigo-500 text-indigo-600 dark:border-indigo-400 dark:text-indigo-400'
+                        : 'border-transparent text-gray-500 hover:border-gray-300 hover:text-gray-700 dark:text-gray-400 dark:hover:border-white/20 dark:hover:text-gray-300',
+                      'group inline-flex items-center border-b-2 px-1 py-4 text-sm font-medium',
+                    )}
+                  >
+                    {Icon && (
+                      <Icon
+                        aria-hidden="true"
+                        className={classNames(
+                          active
+                            ? 'text-indigo-500 dark:text-indigo-400'
+                            : 'text-gray-400 group-hover:text-gray-500 dark:text-gray-500 dark:group-hover:text-gray-400',
+                          'mr-2 -ml-0.5 size-5',
+                        )}
+                      />
+                    )}
+                    <span>{tab.name}</span>
+                  </Link>
+                )
+              })}
+            </nav>
+          </div>
+        )}
+
+        {variant === 'pills' && (
+          <div className="border-b border-gray-200 px-4 py-3 sm:px-6 lg:px-8 dark:border-white/10">
+            <nav aria-label={ariaLabel} className={classNames('flex space-x-4', alignClassName)}>
+              {tabs.map((tab) => {
+                const active = isTabActive(tab, location.pathname)
+
+                return (
+                  <Link
+                    key={tab.name}
+                    to={tab.href}
+                    aria-current={active ? 'page' : undefined}
+                    className={classNames(
+                      active
+                        ? 'bg-gray-100 text-gray-700 dark:bg-white/10 dark:text-gray-200'
+                        : 'text-gray-500 hover:text-gray-700 dark:text-gray-400 dark:hover:text-gray-200',
+                      'rounded-md px-3 py-2 text-sm font-medium',
+                    )}
+                  >
+                    {tab.name}
+                  </Link>
+                )
+              })}
+            </nav>
+          </div>
+        )}
+
+        {variant === 'pills-gray' && (
+          <div className="border-b border-gray-200 px-4 py-3 sm:px-6 lg:px-8 dark:border-white/10">
+            <nav aria-label={ariaLabel} className={classNames('flex space-x-4', alignClassName)}>
+              {tabs.map((tab) => {
+                const active = isTabActive(tab, location.pathname)
+
+                return (
+                  <Link
+                    key={tab.name}
+                    to={tab.href}
+                    aria-current={active ? 'page' : undefined}
+                    className={classNames(
+                      active
+                        ? 'bg-gray-200 text-gray-800 dark:bg-white/10 dark:text-white'
+                        : 'text-gray-600 hover:text-gray-800 dark:text-gray-400 dark:hover:text-white',
+                      'rounded-md px-3 py-2 text-sm font-medium',
+                    )}
+                  >
+                    {tab.name}
+                  </Link>
+                )
+              })}
+            </nav>
+          </div>
+        )}
+
+        {variant === 'pills-brand' && (
+          <div className="border-b border-gray-200 px-4 py-3 sm:px-6 lg:px-8 dark:border-white/10">
+            <nav aria-label={ariaLabel} className={classNames('flex space-x-4', alignClassName)}>
+              {tabs.map((tab) => {
+                const active = isTabActive(tab, location.pathname)
+
+                return (
+                  <Link
+                    key={tab.name}
+                    to={tab.href}
+                    aria-current={active ? 'page' : undefined}
+                    className={classNames(
+                      active
+                        ? 'bg-indigo-100 text-indigo-700 dark:bg-indigo-500/20 dark:text-indigo-300'
+                        : 'text-gray-500 hover:text-gray-700 dark:text-gray-400 dark:hover:text-gray-200',
+                      'rounded-md px-3 py-2 text-sm font-medium',
+                    )}
+                  >
+                    {tab.name}
+                  </Link>
+                )
+              })}
+            </nav>
+          </div>
+        )}
+
+        {variant === 'full-width-underline' && (
+          <div className="border-b border-gray-200 dark:border-white/10">
+            <nav aria-label={ariaLabel} className="-mb-px flex">
+              {tabs.map((tab) => {
+                const active = isTabActive(tab, location.pathname)
+
+                return (
+                  <Link
+                    key={tab.name}
+                    to={tab.href}
+                    aria-current={active ? 'page' : undefined}
+                    className={classNames(
+                      active
+                        ? 'border-indigo-500 text-indigo-600 dark:border-indigo-400 dark:text-indigo-400'
+                        : 'border-transparent text-gray-500 hover:border-gray-300 hover:text-gray-700 dark:text-gray-400 dark:hover:border-white/20 dark:hover:text-gray-300',
+                      'flex-1 border-b-2 px-1 py-4 text-center text-sm font-medium',
+                    )}
+                  >
+                    {tab.name}
+                  </Link>
+                )
+              })}
+            </nav>
+          </div>
+        )}
+
+        {variant === 'bar-underline' && (
+          <nav
+            aria-label={ariaLabel}
+            className="isolate flex divide-x divide-gray-200 rounded-lg bg-white shadow-sm dark:divide-white/10 dark:bg-gray-800/50 dark:shadow-none dark:outline dark:-outline-offset-1 dark:outline-white/10"
+          >
+            {tabs.map((tab, tabIndex) => {
+              const active = isTabActive(tab, location.pathname)
+
+              return (
+                <Link
+                  key={tab.name}
+                  to={tab.href}
+                  aria-current={active ? 'page' : undefined}
+                  className={classNames(
+                    active
+                      ? 'text-gray-900 dark:text-white'
+                      : 'text-gray-500 hover:text-gray-700 dark:text-gray-400 dark:hover:text-white',
+                    tabIndex === 0 && 'rounded-l-lg',
+                    tabIndex === tabs.length - 1 && 'rounded-r-lg',
+                    'group relative min-w-0 flex-1 overflow-hidden px-4 py-4 text-center text-sm font-medium hover:bg-gray-50 focus:z-10 dark:hover:bg-white/5',
+                  )}
+                >
+                  <span>{tab.name}</span>
+                  <span
+                    aria-hidden="true"
+                    className={classNames(
+                      active ? 'bg-indigo-500 dark:bg-indigo-400' : 'bg-transparent',
+                      'absolute inset-x-0 bottom-0 h-0.5',
+                    )}
+                  />
+                </Link>
+              )
+            })}
+          </nav>
+        )}
+
+        {variant === 'underline-badges' && (
+          <div className="border-b border-gray-200 dark:border-white/10">
+            <nav aria-label={ariaLabel} className={classNames('-mb-px flex space-x-8', alignClassName)}>
+              {tabs.map((tab) => {
+                const active = isTabActive(tab, location.pathname)
+
+                return (
+                  <Link
+                    key={tab.name}
+                    to={tab.href}
+                    aria-current={active ? 'page' : undefined}
+                    className={classNames(
+                      active
+                        ? 'border-indigo-500 text-indigo-600 dark:border-indigo-400 dark:text-indigo-400'
+                        : 'border-transparent text-gray-500 hover:border-gray-200 hover:text-gray-700 dark:text-gray-400 dark:hover:border-white/20 dark:hover:text-white',
+                      'flex border-b-2 px-1 py-4 text-sm font-medium whitespace-nowrap',
+                    )}
+                  >
+                    {tab.name}
+
+                    {tab.count ? (
+                      <span
+                        className={classNames(
+                          active
+                            ? 'bg-indigo-100 text-indigo-600 dark:bg-indigo-500/20 dark:text-indigo-400'
+                            : 'bg-gray-100 text-gray-900 dark:bg-white/10 dark:text-gray-300',
+                          'ml-3 hidden rounded-full px-2.5 py-0.5 text-xs font-medium md:inline-block',
+                        )}
+                      >
+                        {tab.count}
+                      </span>
+                    ) : null}
+                  </Link>
+                )
+              })}
+            </nav>
+          </div>
+        )}
+
+        {variant === 'simple' && (
+          <nav
+            aria-label={ariaLabel}
+            className="flex overflow-x-auto border-b border-gray-200 dark:border-white/10"
+          >
+            <ul
+              role="list"
+              className={classNames(
+                'flex min-w-full flex-none gap-x-6 px-4 py-3 text-sm/6 font-semibold text-gray-500 sm:px-6 lg:px-8 dark:text-gray-400',
+                alignClassName,
+              )}
+            >
+              {tabs.map((tab) => {
+                const active = isTabActive(tab, location.pathname)
+
+                return (
+                  <li key={tab.name}>
+                    <Link
+                      to={tab.href}
+                      aria-current={active ? 'page' : undefined}
+                      className={
+                        active
+                          ? 'text-indigo-600 dark:text-indigo-400'
+                          : 'hover:text-gray-700 dark:hover:text-white'
+                      }
+                    >
+                      {tab.name}
+                    </Link>
+                  </li>
+                )
+              })}
+            </ul>
+          </nav>
+        )}
+      </div>
+    </div>
+  )
+}

frontend/src/components/Topbar.tsx

@@ -0,0 +1,132 @@
+// frontend/src/components/Topbar.tsx
+
+import {
+  Menu,
+  MenuButton,
+  MenuItem,
+  MenuItems,
+} from '@headlessui/react'
+import {
+  Bars3Icon,
+  BellIcon,
+} from '@heroicons/react/24/outline'
+import { ChevronDownIcon } from '@heroicons/react/20/solid'
+import { Link } from 'react-router'
+import Search from './Search'
+import Camera from './Camera'
+import type { User } from './types'
+
+type TopbarProps = {
+  user: User
+  onLogout: () => void | Promise<void>
+  onOpenSidebar: () => void
+}
+
+const userNavigation = [
+  { name: 'Mein Account', href: '/einstellungen' },
+]
+
+export default function Topbar({ user, onLogout, onOpenSidebar }: TopbarProps) {
+  function handleQrScan(value: string) {
+    console.log('QR-Code erkannt:', value)
+  }
+
+  const avatarUrl =
+    user.avatar ||
+    'https://images.unsplash.com/photo-1472099645785-5658abf4ff4e?ixlib=rb-1.2.1&ixid=eyJhcHBfaWQiOjEyMDd9&auto=format&fit=facearea&facepad=2&w=256&h=256&q=80'
+
+  return (
+    <div className="sticky top-0 z-40 flex h-16 shrink-0 items-center gap-x-4 border-b border-gray-200 bg-white px-4 shadow-xs sm:gap-x-6 sm:px-6 lg:px-8 dark:border-white/10 dark:bg-gray-900">
+      <button
+        type="button"
+        onClick={onOpenSidebar}
+        className="-m-2.5 p-2.5 text-gray-700 hover:text-gray-900 lg:hidden dark:text-gray-400 dark:hover:text-white"
+      >
+        <span className="sr-only">Open sidebar</span>
+        <Bars3Icon aria-hidden="true" className="size-6" />
+      </button>
+
+      <div aria-hidden="true" className="h-6 w-px bg-gray-900/10 lg:hidden dark:bg-white/10" />
+
+      <div className="flex flex-1 gap-x-3 self-stretch lg:gap-x-4">
+        <div className="flex items-center">
+          <Camera onScan={handleQrScan} />
+        </div>
+
+        <div
+          aria-hidden="true"
+          className="hidden h-6 w-px self-center bg-gray-900/10 lg:block dark:bg-white/10"
+        />
+
+        <Search />
+
+        <div className="flex items-center gap-x-4 lg:gap-x-6">
+          <button
+            type="button"
+            className="-m-2.5 p-2.5 text-gray-400 hover:text-gray-500 dark:text-gray-400 dark:hover:text-gray-300"
+          >
+            <span className="sr-only">View notifications</span>
+            <BellIcon aria-hidden="true" className="size-6" />
+          </button>
+
+          <div
+            aria-hidden="true"
+            className="hidden lg:block lg:h-6 lg:w-px lg:bg-gray-900/10 dark:lg:bg-gray-100/10"
+          />
+
+          <Menu as="div" className="relative">
+            <MenuButton className="relative flex items-center">
+              <span className="absolute -inset-1.5" />
+              <span className="sr-only">Open user menu</span>
+
+              <img
+                alt=""
+                src={avatarUrl}
+                className="size-8 rounded-full bg-gray-50 object-cover outline -outline-offset-1 outline-black/5 dark:bg-gray-800 dark:outline-white/10"
+              />
+
+              <span className="hidden lg:flex lg:items-center">
+                <span
+                  aria-hidden="true"
+                  className="ml-4 text-sm/6 font-semibold text-gray-900 dark:text-white"
+                >
+                  {user.displayName || user.username}
+                </span>
+                <ChevronDownIcon
+                  aria-hidden="true"
+                  className="ml-2 size-5 text-gray-400 dark:text-gray-500"
+                />
+              </span>
+            </MenuButton>
+
+            <MenuItems
+              transition
+              className="absolute right-0 z-10 mt-2.5 w-40 origin-top-right rounded-md bg-white py-2 shadow-lg outline outline-gray-900/5 transition data-closed:scale-95 data-closed:transform data-closed:opacity-0 data-enter:duration-100 data-enter:ease-out data-leave:duration-75 data-leave:ease-in dark:bg-gray-800 dark:shadow-none dark:-outline-offset-1 dark:outline-white/10"
+            >
+              {userNavigation.map((item) => (
+                <MenuItem key={item.name}>
+                  <Link
+                    to={item.href}
+                    className="block px-3 py-1 text-sm/6 text-gray-900 data-focus:bg-gray-50 data-focus:outline-hidden dark:text-white dark:data-focus:bg-white/5"
+                  >
+                    {item.name}
+                  </Link>
+                </MenuItem>
+              ))}
+
+              <MenuItem>
+                <button
+                  type="button"
+                  onClick={onLogout}
+                  className="block w-full px-3 py-1 text-left text-sm/6 text-gray-900 data-focus:bg-gray-50 data-focus:outline-hidden dark:text-white dark:data-focus:bg-white/5"
+                >
+                  Abmelden
+                </button>
+              </MenuItem>
+            </MenuItems>
+          </Menu>
+        </div>
+      </div>
+    </div>
+  )
+}

frontend/src/components/types.ts

@@ -0,0 +1,38 @@
+// frontend\src\components\types.ts
+
+export type Team = {
+  id: string
+  name: string
+  initial: string
+  href: string
+  current: boolean
+}
+
+export type User = {
+  id: string
+  username: string
+  displayName: string
+  email: string
+  avatar: string
+  unit: string
+  group: string
+  rights: string[]
+  teams: Team[]
+}
+
+export type DeviceHistoryChange = {
+  field: string
+  label: string
+  oldValue: string
+  newValue: string
+}
+
+export type DeviceHistoryEntry = {
+  id: string
+  deviceId: string
+  userId: string
+  userDisplayName: string
+  action: 'created' | 'updated'
+  changes: DeviceHistoryChange[]
+  createdAt: string
+}

frontend/src/index.css

@@ -0,0 +1,13 @@
+/* frontend\src\index.css */
+
+@import "tailwindcss";
+
+html,
+body,
+#root {
+  min-height: 100%;
+}
+
+body {
+  margin: 0;
+}

frontend/src/main.tsx

@@ -0,0 +1,15 @@
+// main.tsx
+
+import { StrictMode } from 'react'
+import { createRoot } from 'react-dom/client'
+import { BrowserRouter } from 'react-router'
+import './index.css'
+import App from './App.tsx'
+
+createRoot(document.getElementById('root')!).render(
+  <StrictMode>
+    <BrowserRouter>
+      <App />
+    </BrowserRouter>
+  </StrictMode>,
+)

frontend/src/pages/CalendarPage.tsx

@@ -0,0 +1,11 @@
+// frontend/src/pages/CalendarPage.tsx
+
+export default function CalendarPage() {
+  return (
+    <div className="px-4 py-10 sm:px-6 lg:px-8">
+      <h1 className="text-2xl font-semibold text-gray-900 dark:text-white">
+        Kalender
+      </h1>
+    </div>
+  )
+}

frontend/src/pages/DashboardPage.tsx

@@ -0,0 +1,19 @@
+// frontend\src\pages\DashboardPage.tsx
+
+type DashboardPageProps = {
+  username: string
+}
+
+export default function DashboardPage({ username }: DashboardPageProps) {
+  return (
+    <div className="px-4 py-10 sm:px-6 lg:px-8">
+      <h1 className="text-2xl font-semibold text-gray-900 dark:text-white">
+        Dashboard
+      </h1>
+
+      <p className="mt-2 text-sm text-gray-500 dark:text-gray-400">
+        Willkommen zurück, {username}.
+      </p>
+    </div>
+  )
+}

frontend/src/pages/DevicesPage.tsx

@@ -0,0 +1,698 @@
+// frontend/src/pages/DevicesPage.tsx
+
+import { useEffect, useState, type FormEvent } from 'react'
+import {
+  Dialog,
+  DialogBackdrop,
+  DialogPanel,
+  DialogTitle,
+} from '@headlessui/react'
+import { XMarkIcon } from '@heroicons/react/24/outline'
+import Feed, { type FeedTimelineItem } from '../components/Feed'
+import { PencilSquareIcon, PlusCircleIcon } from '@heroicons/react/20/solid'
+import Tables, { type TableColumn } from '../components/Tables'
+import Button from '../components/Button'
+import type { DeviceHistoryChange, DeviceHistoryEntry } from '../components/types'
+
+const API_URL = import.meta.env.VITE_API_URL ?? 'http://localhost:8080'
+
+type RelatedDevice = {
+  id: string
+  inventoryNumber: string
+  manufacturer: string
+  model: string
+}
+
+type Device = {
+  id: string
+  inventoryNumber: string
+  manufacturer: string
+  model: string
+  serialNumber: string
+  macAddress: string
+  location: string
+  loanStatus: string
+  comment: string
+  relatedDevices: RelatedDevice[]
+}
+
+const inputClassName =
+  'block w-full rounded-md bg-white px-3 py-1.5 text-base text-gray-900 outline-1 -outline-offset-1 outline-gray-300 placeholder:text-gray-400 focus:outline-2 focus:-outline-offset-2 focus:outline-indigo-600 sm:text-sm/6 dark:bg-white/5 dark:text-white dark:outline-white/10 dark:placeholder:text-gray-500 dark:focus:outline-indigo-500'
+
+const selectClassName =
+  'block w-full rounded-md bg-white px-3 py-1.5 text-base text-gray-900 outline-1 -outline-offset-1 outline-gray-300 focus:outline-2 focus:-outline-offset-2 focus:outline-indigo-600 sm:text-sm/6 dark:bg-white/5 dark:text-white dark:outline-white/10 dark:*:bg-gray-800 dark:focus:outline-indigo-500'
+
+function getLoanStatusClassName(status: string) {
+  const normalizedStatus = status.toLowerCase()
+
+  if (
+    normalizedStatus.includes('ausgeliehen') ||
+    normalizedStatus.includes('verliehen') ||
+    normalizedStatus.includes('reserviert')
+  ) {
+    return 'bg-amber-50 text-amber-700 ring-amber-600/20 dark:bg-amber-900/30 dark:text-amber-300 dark:ring-amber-500/30'
+  }
+
+  if (
+    normalizedStatus.includes('defekt') ||
+    normalizedStatus.includes('verloren') ||
+    normalizedStatus.includes('gesperrt')
+  ) {
+    return 'bg-red-50 text-red-700 ring-red-600/20 dark:bg-red-900/30 dark:text-red-400 dark:ring-red-500/30'
+  }
+
+  if (
+    normalizedStatus.includes('wartung') ||
+    normalizedStatus.includes('prüfung')
+  ) {
+    return 'bg-blue-50 text-blue-700 ring-blue-600/20 dark:bg-blue-900/30 dark:text-blue-300 dark:ring-blue-500/30'
+  }
+
+  return 'bg-green-50 text-green-700 ring-green-600/20 dark:bg-green-900/30 dark:text-green-400 dark:ring-green-500/30'
+}
+
+function formatHistoryDate(value: string) {
+  try {
+    return new Intl.DateTimeFormat('de-DE', {
+      dateStyle: 'short',
+      timeStyle: 'short',
+    }).format(new Date(value))
+  } catch {
+    return value
+  }
+}
+
+function formatHistoryChange(change: DeviceHistoryChange) {
+  return `${change.label}: ${change.oldValue} → ${change.newValue}`
+}
+
+function getHistoryContent(entry: DeviceHistoryEntry) {
+  if (entry.action === 'created') {
+    return 'Gerät erstellt durch'
+  }
+
+  if (!entry.changes.length) {
+    return 'Gerät bearbeitet durch'
+  }
+
+  return `${entry.changes.map(formatHistoryChange).join(', ')} durch`
+}
+
+export default function DevicesPage() {
+  const [devices, setDevices] = useState<Device[]>([])
+  const [isLoading, setIsLoading] = useState(true)
+  const [isCreateModalOpen, setIsCreateModalOpen] = useState(false)
+  const [isCreating, setIsCreating] = useState(false)
+  const [error, setError] = useState<string | null>(null)
+  const [createError, setCreateError] = useState<string | null>(null)
+  const [relatedDeviceIds, setRelatedDeviceIds] = useState<string[]>([])
+  const [currentDeviceId, setCurrentDeviceId] = useState<string | null>(null)
+  const [editingDevice, setEditingDevice] = useState<Device | null>(null)
+
+  const [deviceHistory, setDeviceHistory] = useState<DeviceHistoryEntry[]>([])
+  const [isHistoryLoading, setIsHistoryLoading] = useState(false)
+  const [historyError, setHistoryError] = useState<string | null>(null)
+
+  const isEditing = editingDevice !== null
+
+  useEffect(() => {
+    loadDevices()
+  }, [])
+
+  async function loadDevices() {
+    setIsLoading(true)
+    setError(null)
+
+    try {
+      const response = await fetch(`${API_URL}/devices`, {
+        credentials: 'include',
+      })
+
+      if (!response.ok) {
+        const errorData = await response.json().catch(() => null)
+        throw new Error(errorData?.error ?? 'Geräte konnten nicht geladen werden')
+      }
+
+      const data = await response.json()
+      setDevices(data.devices ?? [])
+    } catch (error) {
+      setError(error instanceof Error ? error.message : 'Geräte konnten nicht geladen werden')
+    } finally {
+      setIsLoading(false)
+    }
+  }
+
+  async function loadDeviceHistory(deviceId: string) {
+    setIsHistoryLoading(true)
+    setHistoryError(null)
+
+    try {
+      const response = await fetch(`${API_URL}/devices/${deviceId}/history`, {
+        credentials: 'include',
+      })
+
+      if (!response.ok) {
+        const errorData = await response.json().catch(() => null)
+        throw new Error(errorData?.error ?? 'Bearbeitungsverlauf konnte nicht geladen werden')
+      }
+
+      const data = await response.json()
+      setDeviceHistory(data.history ?? [])
+    } catch (error) {
+      setHistoryError(
+        error instanceof Error
+          ? error.message
+          : 'Bearbeitungsverlauf konnte nicht geladen werden',
+      )
+    } finally {
+      setIsHistoryLoading(false)
+    }
+  }
+
+  function openCreateModal() {
+    setCreateError(null)
+    setEditingDevice(null)
+    setRelatedDeviceIds([])
+    setCurrentDeviceId(null)
+    setIsCreateModalOpen(true)
+  }
+
+  function closeCreateModal() {
+    if (isCreating) {
+      return
+    }
+
+    setIsCreateModalOpen(false)
+    setEditingDevice(null)
+    setCurrentDeviceId(null)
+    setRelatedDeviceIds([])
+    setDeviceHistory([])
+    setHistoryError(null)
+    setIsHistoryLoading(false)
+  }
+
+  function openEditModal(device: Device) {
+    setCreateError(null)
+    setHistoryError(null)
+    setDeviceHistory([])
+    setEditingDevice(device)
+    setCurrentDeviceId(device.id)
+    setRelatedDeviceIds(device.relatedDevices?.map((relatedDevice) => relatedDevice.id) ?? [])
+    setIsCreateModalOpen(true)
+
+    void loadDeviceHistory(device.id)
+  }
+
+  function toggleRelatedDevice(deviceId: string) {
+    setRelatedDeviceIds((currentDeviceIds) => {
+      if (currentDeviceIds.includes(deviceId)) {
+        return currentDeviceIds.filter((currentDeviceId) => currentDeviceId !== deviceId)
+      }
+
+      return [...currentDeviceIds, deviceId]
+    })
+  }
+
+  async function handleSaveDevice(event: FormEvent<HTMLFormElement>) {
+    event.preventDefault()
+
+    const form = event.currentTarget
+    const formData = new FormData(form)
+
+    setIsCreating(true)
+    setCreateError(null)
+
+    const payload = {
+      inventoryNumber: String(formData.get('inventoryNumber') ?? ''),
+      manufacturer: String(formData.get('manufacturer') ?? ''),
+      model: String(formData.get('model') ?? ''),
+      serialNumber: String(formData.get('serialNumber') ?? ''),
+      macAddress: String(formData.get('macAddress') ?? ''),
+      location: String(formData.get('location') ?? ''),
+      loanStatus: String(formData.get('loanStatus') ?? 'Verfügbar'),
+      comment: String(formData.get('comment') ?? ''),
+      relatedDeviceIds,
+    }
+
+    try {
+      const response = await fetch(
+        isEditing
+          ? `${API_URL}/devices/${editingDevice.id}`
+          : `${API_URL}/devices`,
+        {
+          method: isEditing ? 'PUT' : 'POST',
+          headers: {
+            'Content-Type': 'application/json',
+          },
+          credentials: 'include',
+          body: JSON.stringify(payload),
+        },
+      )
+
+      if (!response.ok) {
+        const errorData = await response.json().catch(() => null)
+        throw new Error(
+          errorData?.error ??
+            (isEditing ? 'Gerät konnte nicht aktualisiert werden' : 'Gerät konnte nicht erstellt werden'),
+        )
+      }
+
+      form.reset()
+      setRelatedDeviceIds([])
+      setEditingDevice(null)
+      setCurrentDeviceId(null)
+      setIsCreateModalOpen(false)
+
+      await loadDevices()
+    } catch (error) {
+      setCreateError(
+        error instanceof Error
+          ? error.message
+          : isEditing
+            ? 'Gerät konnte nicht aktualisiert werden'
+            : 'Gerät konnte nicht erstellt werden',
+      )
+    } finally {
+      setIsCreating(false)
+    }
+  }
+
+  const columns: TableColumn<Device>[] = [
+    {
+      key: 'inventoryNumber',
+      header: 'Inventur-Nr.',
+      isPrimary: true,
+      render: (device) => device.inventoryNumber,
+    },
+    {
+      key: 'manufacturer',
+      header: 'Hersteller',
+      render: (device) => device.manufacturer || '-',
+    },
+    {
+      key: 'model',
+      header: 'Modell',
+      render: (device) => device.model || '-',
+    },
+    {
+      key: 'serialNumber',
+      header: 'Seriennummer',
+      hideOnMobile: 'lg',
+      render: (device) => device.serialNumber || '-',
+    },
+    {
+      key: 'macAddress',
+      header: 'MAC-Adresse',
+      hideOnMobile: 'lg',
+      render: (device) => device.macAddress || '-',
+    },
+    {
+      key: 'location',
+      header: 'Standort',
+      render: (device) => device.location || '-',
+    },
+    {
+      key: 'loanStatus',
+      header: 'Verleih-Status',
+      render: (device) => (
+        <span
+          className={[
+            'inline-flex items-center rounded-md px-2 py-1 text-xs font-medium ring-1 ring-inset',
+            getLoanStatusClassName(device.loanStatus),
+          ].join(' ')}
+        >
+          {device.loanStatus || 'Verfügbar'}
+        </span>
+      ),
+    },
+    {
+      key: 'relatedDevices',
+      header: 'Zubehör',
+      hideOnMobile: 'lg',
+      render: (device) => {
+        if (!device.relatedDevices?.length) {
+          return '-'
+        }
+
+        return (
+          <div className="flex max-w-xs flex-wrap gap-1">
+            {device.relatedDevices.map((relatedDevice) => (
+              <span
+                key={relatedDevice.id}
+                className="inline-flex items-center rounded-md bg-gray-50 px-2 py-1 text-xs font-medium text-gray-600 ring-1 ring-gray-500/10 ring-inset dark:bg-white/5 dark:text-gray-300 dark:ring-white/10"
+              >
+                {relatedDevice.inventoryNumber}
+              </span>
+            ))}
+          </div>
+        )
+      },
+    },
+    {
+      key: 'comment',
+      header: 'Kommentar',
+      hideOnMobile: 'lg',
+      render: (device) => (
+        <span className="block max-w-xs truncate">
+          {device.comment || '-'}
+        </span>
+      ),
+    },
+  ]
+
+  const assignableDevices = devices.filter((device) => device.id !== currentDeviceId)
+
+  const historyTimeline: FeedTimelineItem[] = deviceHistory.map((entry) => ({
+    id: entry.id,
+    content: getHistoryContent(entry),
+    target: entry.userDisplayName || 'Unbekannt',
+    href: '#',
+    date: formatHistoryDate(entry.createdAt),
+    datetime: entry.createdAt,
+    icon: entry.action === 'created' ? PlusCircleIcon : PencilSquareIcon,
+    iconBackground: entry.action === 'created' ? 'bg-green-500' : 'bg-blue-500',
+  }))
+
+  return (
+    <div className="px-4 py-10 sm:px-6 lg:px-8">
+      {error && (
+        <div className="mb-6 rounded-md bg-red-50 p-4 text-sm text-red-700 dark:bg-red-900/30 dark:text-red-300">
+          {error}
+        </div>
+      )}
+
+      <Tables
+        title="Geräte"
+        description={
+          isLoading
+            ? 'Geräte werden geladen...'
+            : 'Eine Liste aller Geräte inklusive Inventur-Nr., Hersteller, Modell, Seriennummer, MAC-Adresse, Standort, Verleih-Status und Zubehör.'
+        }
+        actionLabel="Gerät hinzufügen"
+        onAction={openCreateModal}
+        rows={devices}
+        columns={columns}
+        getRowId={(device) => device.id}
+        variant="card"
+        emptyText={isLoading ? 'Geräte werden geladen...' : 'Keine Geräte vorhanden.'}
+        rowActions={(device) => (
+          <button
+            type="button"
+            onClick={() => openEditModal(device)}
+            className="text-indigo-600 hover:text-indigo-900 dark:text-indigo-400 dark:hover:text-indigo-300"
+          >
+            Bearbeiten<span className="sr-only">, {device.inventoryNumber}</span>
+          </button>
+        )}
+      />
+
+      <Dialog open={isCreateModalOpen} onClose={closeCreateModal} className="relative z-50">
+        <DialogBackdrop
+          transition
+          className="fixed inset-0 bg-gray-900/50 transition-opacity data-closed:opacity-0 dark:bg-gray-950/70"
+        />
+
+        <div className="fixed inset-0 overflow-y-auto">
+          <div className="flex min-h-full items-center justify-center p-4">
+            <DialogPanel
+              transition
+              className={[
+                'w-full transform overflow-hidden rounded-lg bg-white shadow-xl outline outline-gray-900/5 transition data-closed:scale-95 data-closed:opacity-0 dark:bg-gray-900 dark:outline-white/10',
+                isEditing ? 'max-w-6xl' : 'max-w-3xl',
+              ].join(' ')}
+            >
+              <form key={editingDevice?.id ?? 'create'} onSubmit={handleSaveDevice}>
+                <div className="flex items-start justify-between border-b border-gray-200 px-4 py-4 sm:px-6 dark:border-white/10">
+                  <div>
+                    <DialogTitle className="text-base font-semibold text-gray-900 dark:text-white">
+                      {isEditing ? 'Gerät bearbeiten' : 'Gerät hinzufügen'}
+                    </DialogTitle>
+                    <p className="mt-1 text-sm text-gray-500 dark:text-gray-400">
+                      {isEditing
+                        ? 'Bearbeite Gerätedaten, Standort, Verleih-Status und Zubehör.'
+                        : 'Erfasse ein neues Gerät inklusive Inventur-Nr., Standort und Zubehör.'}
+                    </p>
+                  </div>
+
+                  <button
+                    type="button"
+                    onClick={closeCreateModal}
+                    className="-m-2.5 rounded-md p-2.5 text-gray-400 hover:text-gray-500 dark:hover:text-gray-300"
+                  >
+                    <span className="sr-only">Schließen</span>
+                    <XMarkIcon aria-hidden="true" className="size-6" />
+                  </button>
+                </div>
+
+                {createError && (
+                  <div className="mx-4 mt-4 rounded-md bg-red-50 p-4 text-sm text-red-700 sm:mx-6 dark:bg-red-900/30 dark:text-red-300">
+                    {createError}
+                  </div>
+                )}
+
+                <div
+                  className={
+                    isEditing
+                      ? 'grid max-h-[calc(100vh-12rem)] grid-cols-1 overflow-y-auto lg:grid-cols-[minmax(0,1fr)_24rem]'
+                      : ''
+                  }
+                >
+                  <div className="grid grid-cols-1 gap-x-6 gap-y-6 px-4 py-6 sm:grid-cols-6 sm:px-6">
+                    <div className="sm:col-span-3">
+                      <label htmlFor="inventoryNumber" className="block text-sm/6 font-medium text-gray-900 dark:text-white">
+                        Inventur-Nr. *
+                      </label>
+                      <div className="mt-2">
+                        <input
+                          id="inventoryNumber"
+                          name="inventoryNumber"
+                          type="text"
+                          required
+                          defaultValue={editingDevice?.inventoryNumber ?? ''}
+                          className={inputClassName}
+                        />
+                      </div>
+                    </div>
+
+                    <div className="sm:col-span-3">
+                      <label htmlFor="loanStatus" className="block text-sm/6 font-medium text-gray-900 dark:text-white">
+                        Verleih-Status
+                      </label>
+                      <div className="mt-2">
+                        <select
+                          id="loanStatus"
+                          name="loanStatus"
+                          defaultValue={editingDevice?.loanStatus || 'Verfügbar'}
+                          className={selectClassName}
+                        >
+                          <option>Verfügbar</option>
+                          <option>Ausgeliehen</option>
+                          <option>Reserviert</option>
+                          <option>Wartung</option>
+                          <option>Defekt</option>
+                          <option>Verloren</option>
+                        </select>
+                      </div>
+                    </div>
+
+                    <div className="sm:col-span-3">
+                      <label htmlFor="manufacturer" className="block text-sm/6 font-medium text-gray-900 dark:text-white">
+                        Hersteller
+                      </label>
+                      <div className="mt-2">
+                        <input
+                          id="manufacturer"
+                          name="manufacturer"
+                          type="text"
+                          defaultValue={editingDevice?.manufacturer ?? ''}
+                          className={inputClassName}
+                        />
+                      </div>
+                    </div>
+
+                    <div className="sm:col-span-3">
+                      <label htmlFor="model" className="block text-sm/6 font-medium text-gray-900 dark:text-white">
+                        Modell
+                      </label>
+                      <div className="mt-2">
+                        <input
+                          id="model"
+                          name="model"
+                          type="text"
+                          defaultValue={editingDevice?.model ?? ''}
+                          className={inputClassName}
+                        />
+                      </div>
+                    </div>
+
+                    <div className="sm:col-span-3">
+                      <label htmlFor="serialNumber" className="block text-sm/6 font-medium text-gray-900 dark:text-white">
+                        Seriennummer
+                      </label>
+                      <div className="mt-2">
+                        <input
+                          id="serialNumber"
+                          name="serialNumber"
+                          type="text"
+                          defaultValue={editingDevice?.serialNumber ?? ''}
+                          className={inputClassName}
+                        />
+                      </div>
+                    </div>
+
+                    <div className="sm:col-span-3">
+                      <label htmlFor="macAddress" className="block text-sm/6 font-medium text-gray-900 dark:text-white">
+                        MAC-Adresse
+                      </label>
+                      <div className="mt-2">
+                        <input
+                          id="macAddress"
+                          name="macAddress"
+                          type="text"
+                          placeholder="00:11:22:33:44:55"
+                          defaultValue={editingDevice?.macAddress ?? ''}
+                          className={inputClassName}
+                        />
+                      </div>
+                    </div>
+
+                    <div className="sm:col-span-6">
+                      <label htmlFor="location" className="block text-sm/6 font-medium text-gray-900 dark:text-white">
+                        Standort
+                      </label>
+                      <div className="mt-2">
+                        <input
+                          id="location"
+                          name="location"
+                          type="text"
+                          defaultValue={editingDevice?.location ?? ''}
+                          className={inputClassName}
+                        />
+                      </div>
+                    </div>
+
+                    <div className="sm:col-span-6">
+                      <label htmlFor="comment" className="block text-sm/6 font-medium text-gray-900 dark:text-white">
+                        Kommentar
+                      </label>
+                      <div className="mt-2">
+                        <textarea
+                          id="comment"
+                          name="comment"
+                          rows={3}
+                          defaultValue={editingDevice?.comment ?? ''}
+                          className={inputClassName}
+                        />
+                      </div>
+                    </div>
+
+                    <div className="sm:col-span-6">
+                      <fieldset>
+                        <legend className="block text-sm/6 font-medium text-gray-900 dark:text-white">
+                          Zugeordnete Geräte / Zubehör
+                        </legend>
+
+                        <div className="mt-2 max-h-44 overflow-y-auto rounded-md border border-gray-200 p-3 dark:border-white/10">
+                          {assignableDevices.length > 0 ? (
+                            <div className="space-y-2">
+                              {assignableDevices.map((device) => (
+                                <label
+                                  key={device.id}
+                                  className="flex items-center gap-x-3 text-sm text-gray-700 dark:text-gray-300"
+                                >
+                                  <input
+                                    type="checkbox"
+                                    checked={relatedDeviceIds.includes(device.id)}
+                                    onChange={() => toggleRelatedDevice(device.id)}
+                                    className="size-4 rounded border-gray-300 text-indigo-600 focus:ring-indigo-600 dark:border-white/10 dark:bg-white/5 dark:focus:ring-indigo-500"
+                                  />
+                                  <span>
+                                    {device.inventoryNumber}
+                                    {(device.manufacturer || device.model) && (
+                                      <span className="text-gray-500 dark:text-gray-400">
+                                        {' '}
+                                        — {[device.manufacturer, device.model].filter(Boolean).join(' ')}
+                                      </span>
+                                    )}
+                                  </span>
+                                </label>
+                              ))}
+                            </div>
+                          ) : (
+                            <p className="text-sm text-gray-500 dark:text-gray-400">
+                              Noch keine anderen Geräte vorhanden.
+                            </p>
+                          )}
+                        </div>
+                      </fieldset>
+                    </div>
+                  </div>
+
+                  {isEditing && (
+                    <aside className="border-t border-gray-200 px-4 py-6 sm:px-6 lg:border-t-0 lg:border-l dark:border-white/10">
+                      <h3 className="text-sm font-semibold text-gray-900 dark:text-white">
+                        Bearbeitungsverlauf
+                      </h3>
+
+                      <p className="mt-1 text-sm text-gray-500 dark:text-gray-400">
+                        Änderungen an diesem Gerät.
+                      </p>
+
+                      <div className="mt-6">
+                        {isHistoryLoading && (
+                          <p className="text-sm text-gray-500 dark:text-gray-400">
+                            Verlauf wird geladen...
+                          </p>
+                        )}
+
+                        {historyError && (
+                          <div className="rounded-md bg-red-50 p-3 text-sm text-red-700 dark:bg-red-900/30 dark:text-red-300">
+                            {historyError}
+                          </div>
+                        )}
+
+                        {!isHistoryLoading && !historyError && historyTimeline.length > 0 && (
+                          <Feed
+                            variant="icons"
+                            timeline={historyTimeline}
+                            showCommentForm={false}
+                          />
+                        )}
+
+                        {!isHistoryLoading && !historyError && historyTimeline.length === 0 && (
+                          <p className="text-sm text-gray-500 dark:text-gray-400">
+                            Noch keine Änderungen erfasst.
+                          </p>
+                        )}
+                      </div>
+                    </aside>
+                  )}
+                </div>
+
+                <div className="flex justify-end gap-x-3 border-t border-gray-200 px-4 py-4 sm:px-6 dark:border-white/10">
+                  <Button
+                    type="button"
+                    variant="secondary"
+                    color="indigo"
+                    onClick={closeCreateModal}
+                    disabled={isCreating}
+                  >
+                    Abbrechen
+                  </Button>
+
+                  <Button
+                    type="submit"
+                    color="indigo"
+                    isLoading={isCreating}
+                  >
+                    {isEditing ? 'Änderungen speichern' : 'Gerät speichern'}
+                  </Button>
+                </div>
+              </form>
+            </DialogPanel>
+          </div>
+        </div>
+      </Dialog>
+    </div>
+  )
+}

frontend/src/pages/DocumentsPage.tsx

@@ -0,0 +1,11 @@
+// frontend/src/pages/DocumentsPage.tsx
+
+export default function DocumentsPage() {
+  return (
+    <div className="px-4 py-10 sm:px-6 lg:px-8">
+      <h1 className="text-2xl font-semibold text-gray-900 dark:text-white">
+        Dokumente
+      </h1>
+    </div>
+  )
+}

frontend/src/pages/IncidentsPage.tsx

@@ -0,0 +1,11 @@
+// frontend/src/pages/IncidentsPage.tsx
+
+export default function IncidentsPage() {
+  return (
+    <div className="px-4 py-10 sm:px-6 lg:px-8">
+      <h1 className="text-2xl font-semibold text-gray-900 dark:text-white">
+        Einsätze
+      </h1>
+    </div>
+  )
+}

frontend/src/pages/ReportsPage.tsx

@@ -0,0 +1,11 @@
+// frontend/src/pages/ReportsPage.tsx
+
+export default function ReportsPage() {
+  return (
+    <div className="px-4 py-10 sm:px-6 lg:px-8">
+      <h1 className="text-2xl font-semibold text-gray-900 dark:text-white">
+        Berichte
+      </h1>
+    </div>
+  )
+}

frontend/src/pages/SettingsPage.tsx

@@ -0,0 +1,357 @@
+// frontend\src\pages\SettingsPage.tsx
+
+import type { FormEvent, ReactNode } from 'react'
+import { useLocation } from 'react-router'
+import {
+  BellIcon,
+  CreditCardIcon,
+  PuzzlePieceIcon,
+  UserIcon,
+  UsersIcon,
+} from '@heroicons/react/20/solid'
+import Tabs from '../components/Tabs'
+import Button from '../components/Button'
+import Container from '../components/Container'
+import type { User } from '../components/types'
+
+type SettingsPageProps = {
+  user?: User
+}
+
+const inputClassName =
+  'block w-full rounded-md bg-white px-3 py-1.5 text-base text-gray-900 outline-1 -outline-offset-1 outline-gray-300 placeholder:text-gray-400 focus:outline-2 focus:-outline-offset-2 focus:outline-indigo-600 sm:text-sm/6 dark:bg-white/5 dark:text-white dark:outline-white/10 dark:placeholder:text-gray-500 dark:focus:outline-indigo-500'
+
+function Section({
+  title,
+  description,
+  children,
+}: {
+  title: string
+  description: string
+  children: ReactNode
+}) {
+  return (
+    <Container variant="constrained" className="py-16">
+      <div className="grid grid-cols-1 gap-x-8 gap-y-10 md:grid-cols-3">
+        <div>
+          <h2 className="text-base/7 font-semibold text-gray-900 dark:text-white">
+            {title}
+          </h2>
+          <p className="mt-1 text-sm/6 text-gray-500 dark:text-gray-400">
+            {description}
+          </p>
+        </div>
+
+        <div className="md:col-span-2">
+          {children}
+        </div>
+      </div>
+    </Container>
+  )
+}
+
+function PlaceholderSection({ title }: { title: string }) {
+  return (
+    <Section
+      title={title}
+      description="Dieser Bereich kann später mit eigenen Einstellungen erweitert werden."
+    >
+      <div className="rounded-lg border border-dashed border-gray-300 p-8 text-sm text-gray-500 dark:border-white/10 dark:text-gray-400">
+        Noch keine Einstellungen vorhanden.
+      </div>
+    </Section>
+  )
+}
+
+export default function SettingsPage({ user }: SettingsPageProps) {
+  const location = useLocation()
+
+  const pathname = location.pathname.replace(/\/$/, '')
+  const section = pathname.split('/')[2] ?? 'konto'
+
+  const settingsTabs = [
+    {
+      name: 'Konto',
+      href: '/einstellungen',
+      icon: UserIcon,
+      current: pathname === '/einstellungen',
+    },
+    {
+      name: 'Benachrichtigungen',
+      href: '/einstellungen/benachrichtigungen',
+      icon: BellIcon,
+      current: pathname === '/einstellungen/benachrichtigungen',
+    },
+    {
+      name: 'Abrechnung',
+      href: '/einstellungen/abrechnung',
+      icon: CreditCardIcon,
+      current: pathname === '/einstellungen/abrechnung',
+    },
+    {
+      name: 'Teams',
+      href: '/einstellungen/teams',
+      icon: UsersIcon,
+      current: pathname === '/einstellungen/teams',
+    },
+    {
+      name: 'Integrationen',
+      href: '/einstellungen/integrationen',
+      icon: PuzzlePieceIcon,
+      current: pathname === '/einstellungen/integrationen',
+    },
+  ]
+
+  const avatarUrl =
+    user?.avatar ||
+    'https://images.unsplash.com/photo-1472099645785-5658abf4ff4e?ixlib=rb-1.2.1&ixid=eyJhcHBfaWQiOjEyMDd9&auto=format&fit=facearea&facepad=2&w=256&h=256&q=80'
+
+  function handleSubmit(event: FormEvent<HTMLFormElement>) {
+    event.preventDefault()
+  }
+
+  return (
+    <main>
+      <h1 className="sr-only">Einstellungen</h1>
+
+      <Tabs
+        tabs={settingsTabs}
+        variant="underline-icons"
+        align="center"
+        sticky
+        stickyTopClassName="top-16"
+        ariaLabel="Einstellungen"
+      />
+
+      {section === 'konto' && (
+        <div className="divide-y divide-gray-200 dark:divide-white/10">
+          <Section
+            title="Persönliche Informationen"
+            description="Verwalte deine Profildaten und Kontoinformationen."
+          >
+            <form onSubmit={handleSubmit}>
+              <div className="grid grid-cols-1 gap-x-6 gap-y-8 sm:max-w-xl sm:grid-cols-6">
+                <div className="col-span-full flex items-center gap-x-8">
+                  <img
+                    alt=""
+                    src={avatarUrl}
+                    className="size-24 flex-none rounded-lg bg-gray-100 object-cover outline -outline-offset-1 outline-black/5 dark:bg-gray-800 dark:outline-white/10"
+                  />
+
+                  <div>
+                    <Button type="button" variant="secondary" size="md">
+                      Avatar ändern
+                    </Button>
+
+                    <p className="mt-2 text-xs/5 text-gray-500 dark:text-gray-400">
+                      JPG, GIF oder PNG. Maximal 1 MB.
+                    </p>
+                  </div>
+                </div>
+
+                <div className="sm:col-span-3">
+                  <label htmlFor="displayName" className="block text-sm/6 font-medium text-gray-900 dark:text-white">
+                    Anzeigename
+                  </label>
+                  <div className="mt-2">
+                    <input
+                      id="displayName"
+                      name="displayName"
+                      type="text"
+                      defaultValue={user?.displayName ?? ''}
+                      className={inputClassName}
+                    />
+                  </div>
+                </div>
+
+                <div className="sm:col-span-3">
+                  <label htmlFor="username" className="block text-sm/6 font-medium text-gray-900 dark:text-white">
+                    Benutzername
+                  </label>
+                  <div className="mt-2">
+                    <input
+                      id="username"
+                      name="username"
+                      type="text"
+                      defaultValue={user?.username ?? ''}
+                      className={inputClassName}
+                    />
+                  </div>
+                </div>
+
+                <div className="col-span-full">
+                  <label htmlFor="email" className="block text-sm/6 font-medium text-gray-900 dark:text-white">
+                    E-Mail-Adresse
+                  </label>
+                  <div className="mt-2">
+                    <input
+                      id="email"
+                      name="email"
+                      type="email"
+                      autoComplete="email"
+                      defaultValue={user?.email ?? ''}
+                      className={inputClassName}
+                    />
+                  </div>
+                </div>
+
+                <div className="sm:col-span-3">
+                  <label htmlFor="unit" className="block text-sm/6 font-medium text-gray-900 dark:text-white">
+                    Einheit
+                  </label>
+                  <div className="mt-2">
+                    <input
+                      id="unit"
+                      name="unit"
+                      type="text"
+                      defaultValue={user?.unit ?? ''}
+                      className={inputClassName}
+                    />
+                  </div>
+                </div>
+
+                <div className="sm:col-span-3">
+                  <label htmlFor="group" className="block text-sm/6 font-medium text-gray-900 dark:text-white">
+                    Gruppe
+                  </label>
+                  <div className="mt-2">
+                    <input
+                      id="group"
+                      name="group"
+                      type="text"
+                      defaultValue={user?.group ?? ''}
+                      className={inputClassName}
+                    />
+                  </div>
+                </div>
+              </div>
+
+              <div className="mt-8 flex">
+                <Button type="submit" color="indigo" size="md">
+                  Speichern
+                </Button>
+              </div>
+            </form>
+          </Section>
+
+          <Section
+            title="Passwort ändern"
+            description="Aktualisiere das Passwort deines Benutzerkontos."
+          >
+            <form onSubmit={handleSubmit}>
+              <div className="grid grid-cols-1 gap-x-6 gap-y-8 sm:max-w-xl sm:grid-cols-6">
+                <div className="col-span-full">
+                  <label htmlFor="current-password" className="block text-sm/6 font-medium text-gray-900 dark:text-white">
+                    Aktuelles Passwort
+                  </label>
+                  <div className="mt-2">
+                    <input
+                      id="current-password"
+                      name="currentPassword"
+                      type="password"
+                      autoComplete="current-password"
+                      className={inputClassName}
+                    />
+                  </div>
+                </div>
+
+                <div className="col-span-full">
+                  <label htmlFor="new-password" className="block text-sm/6 font-medium text-gray-900 dark:text-white">
+                    Neues Passwort
+                  </label>
+                  <div className="mt-2">
+                    <input
+                      id="new-password"
+                      name="newPassword"
+                      type="password"
+                      autoComplete="new-password"
+                      className={inputClassName}
+                    />
+                  </div>
+                </div>
+
+                <div className="col-span-full">
+                  <label htmlFor="confirm-password" className="block text-sm/6 font-medium text-gray-900 dark:text-white">
+                    Neues Passwort bestätigen
+                  </label>
+                  <div className="mt-2">
+                    <input
+                      id="confirm-password"
+                      name="confirmPassword"
+                      type="password"
+                      autoComplete="new-password"
+                      className={inputClassName}
+                    />
+                  </div>
+                </div>
+              </div>
+
+              <div className="mt-8 flex">
+                <Button type="submit" color="indigo" size="md">
+                  Passwort speichern
+                </Button>
+              </div>
+            </form>
+          </Section>
+
+          <Section
+            title="Andere Sitzungen abmelden"
+            description="Melde dich auf anderen Geräten ab, falls du dein Konto absichern möchtest."
+          >
+            <form onSubmit={handleSubmit}>
+              <div className="grid grid-cols-1 gap-x-6 gap-y-8 sm:max-w-xl sm:grid-cols-6">
+                <div className="col-span-full">
+                  <label htmlFor="logout-password" className="block text-sm/6 font-medium text-gray-900 dark:text-white">
+                    Dein Passwort
+                  </label>
+                  <div className="mt-2">
+                    <input
+                      id="logout-password"
+                      name="password"
+                      type="password"
+                      autoComplete="current-password"
+                      className={inputClassName}
+                    />
+                  </div>
+                </div>
+              </div>
+
+              <div className="mt-8 flex">
+                <Button type="submit" color="indigo" size="md">
+                  Andere Sitzungen abmelden
+                </Button>
+              </div>
+            </form>
+          </Section>
+
+          <Section
+            title="Konto löschen"
+            description="Das Löschen deines Kontos kann nicht rückgängig gemacht werden."
+          >
+            <form onSubmit={handleSubmit} className="flex items-start">
+              <Button type="submit" color="red" size="md">
+                Konto löschen
+              </Button>
+            </form>
+          </Section>
+        </div>
+      )}
+
+      {section === 'benachrichtigungen' && (
+        <PlaceholderSection title="Benachrichtigungen" />
+      )}
+
+      {section === 'abrechnung' && (
+        <PlaceholderSection title="Abrechnung" />
+      )}
+
+      {section === 'teams' && (
+        <PlaceholderSection title="Teams" />
+      )}
+
+      {section === 'integrationen' && (
+        <PlaceholderSection title="Integrationen" />
+      )}
+    </main>
+  )
+}

frontend/tsconfig.app.json

@@ -0,0 +1,25 @@
+{
+  "compilerOptions": {
+    "tsBuildInfoFile": "./node_modules/.tmp/tsconfig.app.tsbuildinfo",
+    "target": "es2023",
+    "lib": ["ES2023", "DOM"],
+    "module": "esnext",
+    "types": ["vite/client"],
+    "skipLibCheck": true,
+
+    /* Bundler mode */
+    "moduleResolution": "bundler",
+    "allowImportingTsExtensions": true,
+    "verbatimModuleSyntax": true,
+    "moduleDetection": "force",
+    "noEmit": true,
+    "jsx": "react-jsx",
+
+    /* Linting */
+    "noUnusedLocals": true,
+    "noUnusedParameters": true,
+    "erasableSyntaxOnly": true,
+    "noFallthroughCasesInSwitch": true
+  },
+  "include": ["src"]
+}

frontend/tsconfig.json

@@ -0,0 +1,7 @@
+{
+  "files": [],
+  "references": [
+    { "path": "./tsconfig.app.json" },
+    { "path": "./tsconfig.node.json" }
+  ]
+}

frontend/tsconfig.node.json

@@ -0,0 +1,24 @@
+{
+  "compilerOptions": {
+    "tsBuildInfoFile": "./node_modules/.tmp/tsconfig.node.tsbuildinfo",
+    "target": "es2023",
+    "lib": ["ES2023"],
+    "module": "esnext",
+    "types": ["node"],
+    "skipLibCheck": true,
+
+    /* Bundler mode */
+    "moduleResolution": "bundler",
+    "allowImportingTsExtensions": true,
+    "verbatimModuleSyntax": true,
+    "moduleDetection": "force",
+    "noEmit": true,
+
+    /* Linting */
+    "noUnusedLocals": true,
+    "noUnusedParameters": true,
+    "erasableSyntaxOnly": true,
+    "noFallthroughCasesInSwitch": true
+  },
+  "include": ["vite.config.ts"]
+}

frontend/vite.config.ts

@@ -0,0 +1,11 @@
+import { defineConfig } from 'vite'
+import react from '@vitejs/plugin-react'
+import tailwindcss from '@tailwindcss/vite'
+
+// https://vite.dev/config/
+export default defineConfig({
+  plugins: [
+    react(),
+    tailwindcss(),
+  ],
+})