added calendar + bugfixes

.claude/settings.local.json

@@ -0,0 +1,11 @@
+{
+  "permissions": {
+    "allow": [
+      "PowerShell(Set-Location \"c:\\\\Users\\\\Rother\\\\fork\\\\teg\\\\backend\"; go vet ./... 2>&1 | Select-Object -First 20; \"VET: $LASTEXITCODE\"; gofmt -w chat.go chat_groups.go chat_websocket.go chat_unread.go chat_search.go main.go routes.go setup\\\\main.go; gofmt -l chat.go chat_groups.go chat_websocket.go chat_unread.go chat_search.go; \"fmt done\")",
+      "PowerShell(Set-Location \"c:\\\\Users\\\\Rother\\\\fork\\\\teg\\\\frontend\"; npx tsc --noEmit 2>&1 | Select-Object -First 40; \"TSC EXIT: $LASTEXITCODE\")",
+      "PowerShell(Set-Location \"c:\\\\Users\\\\Rother\\\\fork\\\\teg\\\\frontend\"; npx tsc --noEmit 2>&1 | Select-Object -First 30; \"TSC EXIT: $LASTEXITCODE\")",
+      "Bash(npx tsc *)",
+      "Bash(echo \"EXIT:$?\")"
+    ]
+  }
+}

.gitignore

@@ -75,3 +75,4 @@ $RECYCLE.BIN/
 
 # Windows shortcuts
 *.lnk
+.gocache

backend/.env

@@ -1,7 +1,7 @@
 PORT=8080
 DATABASE_URL=postgres://postgres:Timmy0104199%3F@localhost:5432/teg?sslmode=disable
 JWT_SECRET=tegvideo7010!
-FRONTEND_ORIGIN=http://localhost:5173
+FRONTEND_ORIGIN=https://localhost:5173
 ADDRESS_SEARCH_PROVIDER=photon
 ADDRESS_SEARCH_URL=https://photon.komoot.io/api
 ADDRESS_SEARCH_LANGUAGE=de
@@ -12,9 +12,13 @@ ADDRESS_SEARCH_USER_AGENT=TEG-App/1.0
 ADMIN_USERNAME=admin
 ADMIN_DISPLAY_NAME=Administrator
 ADMIN_EMAIL=admin@tegdssd.de
-ADMIN_UNIT=Administration
+ADMIN_UNIT=TEG
 ADMIN_GROUP=admin
 ADMIN_RIGHTS=admin,users:read,users:write
 ADMIN_TEAM_NAME=Administration
 ADMIN_TEAM_INITIAL=A
 ADMIN_TEAM_HREF=#administration
+
+VAPID_PUBLIC_KEY=BEFezMtT5PwJBOm9VIpP_1Y9Pwn8XAZfOHY2aQI_D9MaWsD3wn87OEdOMLlOa87fmDeB5DMVlpVrRnwBZNbXZ4E
+VAPID_PRIVATE_KEY=3QSvqwejg62ttALunCiib3CXGos2ylvDCDoRGl_OPrQ
+VAPID_SUBSCRIBER=mailto:admin@tegdssd.de

backend/admin.go

@@ -15,12 +15,13 @@ import (
 )
 
 type AdminTeam struct {
-	ID        string    `json:"id"`
+	ID             string    `json:"id"`
-	Name      string    `json:"name"`
+	Name           string    `json:"name"`
-	Initial   string    `json:"initial"`
+	Initial        string    `json:"initial"`
-	Href      string    `json:"href"`
+	Href           string    `json:"href"`
-	CreatedAt time.Time `json:"createdAt"`
+	ConversationID string    `json:"conversationId"`
-	UpdatedAt time.Time `json:"updatedAt"`
+	CreatedAt      time.Time `json:"createdAt"`
+	UpdatedAt      time.Time `json:"updatedAt"`
 }
 
 type AdminUser struct {
@@ -472,16 +473,89 @@ func replaceUserTeams(ctx context.Context, tx pgx.Tx, userID string, teamIDs []s
 		}
 	}
 
+	if _, err := tx.Exec(
+		ctx,
+		`
+		INSERT INTO conversations (type, name, team_id)
+		SELECT 'group', t.name, t.id
+		FROM teams t
+		JOIN user_teams ut
+			ON ut.team_id = t.id
+			AND ut.user_id = $1
+		ON CONFLICT (team_id) WHERE team_id IS NOT NULL
+		DO UPDATE SET
+			type = 'group',
+			name = EXCLUDED.name,
+			created_by = NULL,
+			updated_at = now()
+		`,
+		userID,
+	); err != nil {
+		return err
+	}
+
+	if _, err := tx.Exec(
+		ctx,
+		`
+		DELETE FROM conversation_members cm
+		USING conversations c
+		WHERE cm.conversation_id = c.id
+		  AND cm.user_id = $1
+		  AND c.team_id IS NOT NULL
+		  AND NOT EXISTS (
+			SELECT 1
+			FROM user_teams ut
+			WHERE ut.user_id = cm.user_id
+			  AND ut.team_id = c.team_id
+		  )
+		`,
+		userID,
+	); err != nil {
+		return err
+	}
+
+	if _, err := tx.Exec(
+		ctx,
+		`
+		INSERT INTO conversation_members (conversation_id, user_id)
+		SELECT c.id, $1
+		FROM conversations c
+		JOIN user_teams ut
+			ON ut.team_id = c.team_id
+			AND ut.user_id = $1
+		WHERE c.team_id IS NOT NULL
+		ON CONFLICT (conversation_id, user_id) DO NOTHING
+		`,
+		userID,
+	); err != nil {
+		return err
+	}
+
 	return nil
 }
 
 func (s *Server) handleAdminListTeams(w http.ResponseWriter, r *http.Request) {
+	if err := s.ensureTeamGroupConversations(r.Context()); err != nil {
+		writeError(w, http.StatusInternalServerError, "Team-Gruppenchats konnten nicht vorbereitet werden")
+		return
+	}
+
 	rows, err := s.db.Query(
 		r.Context(),
 		`
-		SELECT id::TEXT, name, initial, href, created_at, updated_at
+		SELECT
-		FROM teams
+			t.id::TEXT,
-		ORDER BY name ASC
+			t.name,
+			t.initial,
+			t.href,
+			COALESCE(c.id::TEXT, ''),
+			t.created_at,
+			t.updated_at
+		FROM teams t
+		LEFT JOIN conversations c
+			ON c.team_id = t.id
+			AND c.type = 'group'
+		ORDER BY t.name ASC
 		`,
 	)
 
@@ -501,6 +575,7 @@ func (s *Server) handleAdminListTeams(w http.ResponseWriter, r *http.Request) {
 			&team.Name,
 			&team.Initial,
 			&team.Href,
+			&team.ConversationID,
 			&team.CreatedAt,
 			&team.UpdatedAt,
 		); err != nil {
@@ -531,24 +606,53 @@ func (s *Server) handleAdminCreateTeam(w http.ResponseWriter, r *http.Request) {
 		return
 	}
 
-	_, err := s.db.Exec(
+	tx, err := s.db.Begin(r.Context())
-		r.Context(),
-		`
-		INSERT INTO teams (name, initial, href)
-		VALUES ($1, $2, $3)
-		`,
-		input.Name,
-		input.Initial,
-		input.Href,
-	)
-
 	if err != nil {
 		writeError(w, http.StatusInternalServerError, "Team konnte nicht erstellt werden")
 		return
 	}
+	defer tx.Rollback(r.Context())
+
+	var teamID string
+	if err := tx.QueryRow(
+		r.Context(),
+		`
+		INSERT INTO teams (name, initial, href)
+		VALUES ($1, $2, $3)
+		RETURNING id::TEXT
+		`,
+		input.Name,
+		input.Initial,
+		input.Href,
+	).Scan(&teamID); err != nil {
+		writeError(w, http.StatusInternalServerError, "Team konnte nicht erstellt werden")
+		return
+	}
+
+	var conversationID string
+	if err := tx.QueryRow(
+		r.Context(),
+		`
+		INSERT INTO conversations (type, name, team_id)
+		VALUES ('group', $1, $2)
+		RETURNING id::TEXT
+		`,
+		input.Name,
+		teamID,
+	).Scan(&conversationID); err != nil {
+		writeError(w, http.StatusInternalServerError, "Team-Gruppenchat konnte nicht erstellt werden")
+		return
+	}
+
+	if err := tx.Commit(r.Context()); err != nil {
+		writeError(w, http.StatusInternalServerError, "Team konnte nicht gespeichert werden")
+		return
+	}
 
 	writeJSON(w, http.StatusCreated, map[string]any{
-		"ok": true,
+		"ok":             true,
+		"id":             teamID,
+		"conversationId": conversationID,
 	})
 }
 
@@ -574,7 +678,14 @@ func (s *Server) handleAdminUpdateTeam(w http.ResponseWriter, r *http.Request) {
 		return
 	}
 
-	_, err := s.db.Exec(
+	tx, err := s.db.Begin(r.Context())
+	if err != nil {
+		writeError(w, http.StatusInternalServerError, "Team konnte nicht aktualisiert werden")
+		return
+	}
+	defer tx.Rollback(r.Context())
+
+	commandTag, err := tx.Exec(
 		r.Context(),
 		`
 		UPDATE teams
@@ -589,13 +700,45 @@ func (s *Server) handleAdminUpdateTeam(w http.ResponseWriter, r *http.Request) {
 		input.Initial,
 		input.Href,
 	)
-
 	if err != nil {
 		writeError(w, http.StatusInternalServerError, "Team konnte nicht aktualisiert werden")
 		return
 	}
+	if commandTag.RowsAffected() == 0 {
+		writeError(w, http.StatusNotFound, "Team wurde nicht gefunden")
+		return
+	}
+
+	var conversationID string
+	if err := tx.QueryRow(
+		r.Context(),
+		`
+		INSERT INTO conversations (type, name, team_id)
+		VALUES ('group', $1, $2)
+		ON CONFLICT (team_id) WHERE team_id IS NOT NULL
+		DO UPDATE SET
+			type = 'group',
+			name = EXCLUDED.name,
+			created_by = NULL,
+			updated_at = now()
+		RETURNING id::TEXT
+		`,
+		input.Name,
+		teamID,
+	).Scan(&conversationID); err != nil {
+		writeError(w, http.StatusInternalServerError, "Team-Gruppenchat konnte nicht aktualisiert werden")
+		return
+	}
+
+	if err := tx.Commit(r.Context()); err != nil {
+		writeError(w, http.StatusInternalServerError, "Team konnte nicht gespeichert werden")
+		return
+	}
+
+	s.publishConversationUpdate(r.Context(), conversationID)
 
 	writeJSON(w, http.StatusOK, map[string]any{
-		"ok": true,
+		"ok":             true,
+		"conversationId": conversationID,
 	})
 }

backend/admin_group_chats.go

@@ -0,0 +1,360 @@
+package main
+
+import (
+	"context"
+	"fmt"
+	"net/http"
+	"strings"
+	"time"
+
+	"github.com/jackc/pgx/v5"
+)
+
+type AdminGroupChat struct {
+	ID        string    `json:"id"`
+	Name      string    `json:"name"`
+	Image     string    `json:"image"`
+	OwnerID   string    `json:"ownerId"`
+	UserIDs   []string  `json:"userIds"`
+	CreatedAt time.Time `json:"createdAt"`
+	UpdatedAt time.Time `json:"updatedAt"`
+}
+
+type saveAdminGroupChatRequest struct {
+	Name    string   `json:"name"`
+	Image   string   `json:"image"`
+	UserIDs []string `json:"userIds"`
+}
+
+func (s *Server) handleAdminListGroupChats(w http.ResponseWriter, r *http.Request) {
+	rows, err := s.db.Query(
+		r.Context(),
+		`
+		SELECT
+			c.id::TEXT,
+			c.name,
+			c.channel_image,
+			COALESCE(c.created_by::TEXT, ''),
+			COALESCE(
+				array_agg(cm.user_id::TEXT ORDER BY cm.created_at)
+					FILTER (WHERE cm.user_id IS NOT NULL),
+				'{}'::TEXT[]
+			),
+			c.created_at,
+			c.updated_at
+		FROM conversations c
+		LEFT JOIN conversation_members cm ON cm.conversation_id = c.id
+		WHERE c.type = 'group'
+		  AND c.team_id IS NULL
+		GROUP BY c.id
+		ORDER BY lower(c.name), c.created_at
+		`,
+	)
+	if err != nil {
+		writeError(w, http.StatusInternalServerError, "Gruppenchats konnten nicht geladen werden")
+		return
+	}
+	defer rows.Close()
+
+	groups := []AdminGroupChat{}
+	for rows.Next() {
+		var group AdminGroupChat
+		if err := rows.Scan(
+			&group.ID,
+			&group.Name,
+			&group.Image,
+			&group.OwnerID,
+			&group.UserIDs,
+			&group.CreatedAt,
+			&group.UpdatedAt,
+		); err != nil {
+			writeError(w, http.StatusInternalServerError, "Gruppenchats konnten nicht gelesen werden")
+			return
+		}
+		groups = append(groups, group)
+	}
+	if err := rows.Err(); err != nil {
+		writeError(w, http.StatusInternalServerError, "Gruppenchats konnten nicht vollständig geladen werden")
+		return
+	}
+	rows.Close()
+
+	users, err := s.listAdminChannelUsers(r.Context())
+	if err != nil {
+		writeError(w, http.StatusInternalServerError, "Benutzer konnten nicht geladen werden")
+		return
+	}
+
+	writeJSON(w, http.StatusOK, map[string]any{
+		"groups": groups,
+		"users":  users,
+	})
+}
+
+func (s *Server) handleAdminUpdateGroupChat(w http.ResponseWriter, r *http.Request) {
+	user, ok := userFromContext(r.Context())
+	if !ok {
+		writeError(w, http.StatusUnauthorized, "Unauthorized")
+		return
+	}
+
+	conversationID := strings.TrimSpace(r.PathValue("id"))
+	if conversationID == "" {
+		writeError(w, http.StatusBadRequest, "Gruppenchat-ID fehlt")
+		return
+	}
+
+	var input saveAdminGroupChatRequest
+	if err := readJSON(r, &input); err != nil {
+		writeError(w, http.StatusBadRequest, "Ungültige Anfrage")
+		return
+	}
+
+	input.Name = strings.TrimSpace(input.Name)
+	input.Image = strings.TrimSpace(input.Image)
+	input.UserIDs = cleanStringList(input.UserIDs)
+	if input.Name == "" || len([]rune(input.Name)) > maxGroupNameLength {
+		writeError(w, http.StatusBadRequest, "Gruppenname muss 1–80 Zeichen lang sein")
+		return
+	}
+	if len(input.Image) > maxGroupImageBytes {
+		writeError(w, http.StatusBadRequest, "Das Gruppenbild ist zu groß")
+		return
+	}
+
+	tx, err := s.db.Begin(r.Context())
+	if err != nil {
+		writeError(w, http.StatusInternalServerError, "Gruppenchat konnte nicht aktualisiert werden")
+		return
+	}
+	defer tx.Rollback(r.Context())
+
+	var currentName, currentImage, ownerID string
+	if err := tx.QueryRow(
+		r.Context(),
+		`
+		SELECT name, channel_image, COALESCE(created_by::TEXT, '')
+		FROM conversations
+		WHERE id = $1
+		  AND type = 'group'
+		  AND team_id IS NULL
+		FOR UPDATE
+		`,
+		conversationID,
+	).Scan(&currentName, &currentImage, &ownerID); err != nil {
+		if err == pgx.ErrNoRows {
+			writeError(w, http.StatusNotFound, "Gruppenchat wurde nicht gefunden")
+			return
+		}
+		writeError(w, http.StatusInternalServerError, "Gruppenchat konnte nicht geladen werden")
+		return
+	}
+
+	if ownerID != "" {
+		input.UserIDs = cleanStringList(append(input.UserIDs, ownerID))
+	}
+	if len(input.UserIDs) == 0 {
+		writeError(w, http.StatusBadRequest, "Mindestens ein Gruppenmitglied ist erforderlich")
+		return
+	}
+
+	oldMemberIDs, err := adminGroupMemberIDs(r.Context(), tx, conversationID)
+	if err != nil {
+		writeError(w, http.StatusInternalServerError, "Gruppenmitglieder konnten nicht geladen werden")
+		return
+	}
+
+	if _, err := tx.Exec(
+		r.Context(),
+		`
+		UPDATE conversations
+		SET
+			name = $2,
+			channel_image = $3,
+			updated_at = now()
+		WHERE id = $1
+		  AND type = 'group'
+		  AND team_id IS NULL
+		`,
+		conversationID,
+		input.Name,
+		input.Image,
+	); err != nil {
+		writeError(w, http.StatusInternalServerError, "Gruppenchat konnte nicht aktualisiert werden")
+		return
+	}
+
+	if _, err := tx.Exec(
+		r.Context(),
+		`
+		DELETE FROM conversation_members
+		WHERE conversation_id = $1
+		  AND NOT (user_id::TEXT = ANY($2::TEXT[]))
+		`,
+		conversationID,
+		input.UserIDs,
+	); err != nil {
+		writeError(w, http.StatusInternalServerError, "Gruppenmitglieder konnten nicht gespeichert werden")
+		return
+	}
+
+	if _, err := tx.Exec(
+		r.Context(),
+		`
+		INSERT INTO conversation_members (conversation_id, user_id)
+		SELECT $1, id
+		FROM users
+		WHERE id::TEXT = ANY($2::TEXT[])
+		ON CONFLICT (conversation_id, user_id) DO NOTHING
+		`,
+		conversationID,
+		input.UserIDs,
+	); err != nil {
+		writeError(w, http.StatusInternalServerError, "Gruppenmitglieder konnten nicht gespeichert werden")
+		return
+	}
+
+	newMemberIDs, err := adminGroupMemberIDs(r.Context(), tx, conversationID)
+	if err != nil || len(newMemberIDs) == 0 {
+		writeError(w, http.StatusBadRequest, "Mindestens ein gültiges Gruppenmitglied ist erforderlich")
+		return
+	}
+
+	if err := tx.Commit(r.Context()); err != nil {
+		writeError(w, http.StatusInternalServerError, "Gruppenchat konnte nicht gespeichert werden")
+		return
+	}
+
+	changed := currentName != input.Name ||
+		currentImage != input.Image ||
+		!sameStringSet(oldMemberIDs, newMemberIDs)
+	if changed {
+		s.emitSystemMessage(
+			r.Context(),
+			conversationID,
+			user.ID,
+			"group_admin_updated",
+			fmt.Sprintf("%s hat den Gruppenchat über die Administration aktualisiert.", conversationActorName(user)),
+			nil,
+		)
+		s.publishConversationUpdate(r.Context(), conversationID)
+	}
+
+	newMembers := make(map[string]struct{}, len(newMemberIDs))
+	for _, memberID := range newMemberIDs {
+		newMembers[memberID] = struct{}{}
+	}
+	for _, memberID := range oldMemberIDs {
+		if _, remains := newMembers[memberID]; remains {
+			continue
+		}
+		chatSockets.publish(memberID, chatSocketEvent{
+			Type:           "conversation.removed",
+			ConversationID: conversationID,
+		})
+	}
+
+	writeJSON(w, http.StatusOK, map[string]any{"id": conversationID})
+}
+
+func (s *Server) handleAdminDeleteGroupChat(w http.ResponseWriter, r *http.Request) {
+	conversationID := strings.TrimSpace(r.PathValue("id"))
+	if conversationID == "" {
+		writeError(w, http.StatusBadRequest, "Gruppenchat-ID fehlt")
+		return
+	}
+
+	memberIDs, err := s.chatConversationMemberIDs(r.Context(), conversationID)
+	if err != nil {
+		writeError(w, http.StatusInternalServerError, "Gruppenmitglieder konnten nicht geladen werden")
+		return
+	}
+
+	tx, err := s.db.Begin(r.Context())
+	if err != nil {
+		writeError(w, http.StatusInternalServerError, "Gruppenchat konnte nicht gelöscht werden")
+		return
+	}
+	defer tx.Rollback(r.Context())
+
+	if _, err := tx.Exec(
+		r.Context(),
+		`DELETE FROM notifications WHERE entity_type = 'chat' AND entity_id = $1`,
+		conversationID,
+	); err != nil {
+		writeError(w, http.StatusInternalServerError, "Chat-Benachrichtigungen konnten nicht gelöscht werden")
+		return
+	}
+
+	commandTag, err := tx.Exec(
+		r.Context(),
+		`DELETE FROM conversations WHERE id = $1 AND type = 'group' AND team_id IS NULL`,
+		conversationID,
+	)
+	if err != nil {
+		writeError(w, http.StatusInternalServerError, "Gruppenchat konnte nicht gelöscht werden")
+		return
+	}
+	if commandTag.RowsAffected() == 0 {
+		writeError(w, http.StatusNotFound, "Gruppenchat wurde nicht gefunden")
+		return
+	}
+
+	if err := tx.Commit(r.Context()); err != nil {
+		writeError(w, http.StatusInternalServerError, "Gruppenchat konnte nicht gelöscht werden")
+		return
+	}
+
+	for _, memberID := range memberIDs {
+		chatSockets.publish(memberID, chatSocketEvent{
+			Type:           "conversation.removed",
+			ConversationID: conversationID,
+		})
+	}
+
+	writeJSON(w, http.StatusOK, map[string]bool{"ok": true})
+}
+
+func adminGroupMemberIDs(ctx context.Context, tx pgx.Tx, conversationID string) ([]string, error) {
+	rows, err := tx.Query(
+		ctx,
+		`
+		SELECT user_id::TEXT
+		FROM conversation_members
+		WHERE conversation_id = $1
+		ORDER BY created_at, user_id
+		`,
+		conversationID,
+	)
+	if err != nil {
+		return nil, err
+	}
+	defer rows.Close()
+
+	memberIDs := []string{}
+	for rows.Next() {
+		var memberID string
+		if err := rows.Scan(&memberID); err != nil {
+			return nil, err
+		}
+		memberIDs = append(memberIDs, memberID)
+	}
+	return memberIDs, rows.Err()
+}
+
+func sameStringSet(left []string, right []string) bool {
+	if len(left) != len(right) {
+		return false
+	}
+
+	values := make(map[string]struct{}, len(left))
+	for _, value := range left {
+		values[value] = struct{}{}
+	}
+	for _, value := range right {
+		if _, exists := values[value]; !exists {
+			return false
+		}
+	}
+	return true
+}

backend/calendar_settings.go

@@ -0,0 +1,217 @@
+package main
+
+import (
+	"encoding/json"
+	"fmt"
+	"net/http"
+	"regexp"
+	"time"
+)
+
+type CalendarWorkingHoursDay struct {
+	Enabled bool   `json:"enabled"`
+	Start   string `json:"start"`
+	End     string `json:"end"`
+}
+
+type CalendarCoreWorkingHours struct {
+	Monday    CalendarWorkingHoursDay `json:"monday"`
+	Tuesday   CalendarWorkingHoursDay `json:"tuesday"`
+	Wednesday CalendarWorkingHoursDay `json:"wednesday"`
+	Thursday  CalendarWorkingHoursDay `json:"thursday"`
+	Friday    CalendarWorkingHoursDay `json:"friday"`
+	Saturday  CalendarWorkingHoursDay `json:"saturday"`
+	Sunday    CalendarWorkingHoursDay `json:"sunday"`
+}
+
+type CalendarSettings struct {
+	CoreWorkingHours CalendarCoreWorkingHours `json:"coreWorkingHours"`
+	UpdatedAt        *time.Time               `json:"updatedAt,omitempty"`
+}
+
+var calendarTimePattern = regexp.MustCompile(`^\d{2}:\d{2}$`)
+
+func defaultCalendarCoreWorkingHours() CalendarCoreWorkingHours {
+	workingDay := CalendarWorkingHoursDay{
+		Enabled: true,
+		Start:   "08:00",
+		End:     "17:00",
+	}
+	dayOff := CalendarWorkingHoursDay{
+		Enabled: false,
+		Start:   "08:00",
+		End:     "17:00",
+	}
+
+	return CalendarCoreWorkingHours{
+		Monday:    workingDay,
+		Tuesday:   workingDay,
+		Wednesday: workingDay,
+		Thursday:  workingDay,
+		Friday:    workingDay,
+		Saturday:  dayOff,
+		Sunday:    dayOff,
+	}
+}
+
+func (s *Server) ensureCalendarSettingsTable(r *http.Request) error {
+	defaultHours, err := json.Marshal(defaultCalendarCoreWorkingHours())
+	if err != nil {
+		return err
+	}
+
+	_, err = s.db.Exec(
+		r.Context(),
+		`
+		CREATE TABLE IF NOT EXISTS calendar_settings (
+			id SMALLINT PRIMARY KEY CHECK (id = 1),
+			core_working_hours JSONB NOT NULL,
+			created_at TIMESTAMPTZ NOT NULL DEFAULT now(),
+			updated_at TIMESTAMPTZ NOT NULL DEFAULT now()
+		)
+		`,
+	)
+	if err != nil {
+		return err
+	}
+
+	_, err = s.db.Exec(
+		r.Context(),
+		`
+		INSERT INTO calendar_settings (id, core_working_hours)
+		VALUES (1, $1::JSONB)
+		ON CONFLICT (id) DO NOTHING
+		`,
+		string(defaultHours),
+	)
+	return err
+}
+
+func (s *Server) loadCalendarSettings(r *http.Request) (CalendarSettings, error) {
+	if err := s.ensureCalendarSettingsTable(r); err != nil {
+		return CalendarSettings{}, err
+	}
+
+	var rawHours []byte
+	var settings CalendarSettings
+	var updatedAt time.Time
+
+	err := s.db.QueryRow(
+		r.Context(),
+		`
+		SELECT core_working_hours, updated_at
+		FROM calendar_settings
+		WHERE id = 1
+		`,
+	).Scan(&rawHours, &updatedAt)
+	if err != nil {
+		return CalendarSettings{}, err
+	}
+
+	if err := json.Unmarshal(rawHours, &settings.CoreWorkingHours); err != nil {
+		return CalendarSettings{}, err
+	}
+
+	settings.UpdatedAt = &updatedAt
+	return settings, nil
+}
+
+func validateCalendarWorkingHours(hours CalendarCoreWorkingHours) error {
+	days := []struct {
+		name  string
+		hours CalendarWorkingHoursDay
+	}{
+		{name: "Montag", hours: hours.Monday},
+		{name: "Dienstag", hours: hours.Tuesday},
+		{name: "Mittwoch", hours: hours.Wednesday},
+		{name: "Donnerstag", hours: hours.Thursday},
+		{name: "Freitag", hours: hours.Friday},
+		{name: "Samstag", hours: hours.Saturday},
+		{name: "Sonntag", hours: hours.Sunday},
+	}
+
+	for _, day := range days {
+		if !calendarTimePattern.MatchString(day.hours.Start) ||
+			!calendarTimePattern.MatchString(day.hours.End) {
+			return fmt.Errorf("%s: Beginn und Ende müssen im Format HH:MM angegeben werden", day.name)
+		}
+
+		start, startErr := time.Parse("15:04", day.hours.Start)
+		end, endErr := time.Parse("15:04", day.hours.End)
+		if startErr != nil || endErr != nil {
+			return fmt.Errorf("%s: ungültige Uhrzeit", day.name)
+		}
+
+		if day.hours.Enabled && !end.After(start) {
+			return fmt.Errorf("%s: das Ende muss nach dem Beginn liegen", day.name)
+		}
+	}
+
+	return nil
+}
+
+func (s *Server) handleGetCalendarSettings(w http.ResponseWriter, r *http.Request) {
+	settings, err := s.loadCalendarSettings(r)
+	if err != nil {
+		writeError(w, http.StatusInternalServerError, "Kalender-Einstellungen konnten nicht geladen werden")
+		return
+	}
+
+	writeJSON(w, http.StatusOK, map[string]any{
+		"settings": settings,
+	})
+}
+
+func (s *Server) handleUpdateCalendarSettings(w http.ResponseWriter, r *http.Request) {
+	var payload struct {
+		CoreWorkingHours CalendarCoreWorkingHours `json:"coreWorkingHours"`
+	}
+
+	if err := readJSON(r, &payload); err != nil {
+		writeError(w, http.StatusBadRequest, "Ungültige Anfrage")
+		return
+	}
+
+	if err := validateCalendarWorkingHours(payload.CoreWorkingHours); err != nil {
+		writeError(w, http.StatusBadRequest, err.Error())
+		return
+	}
+
+	if err := s.ensureCalendarSettingsTable(r); err != nil {
+		writeError(w, http.StatusInternalServerError, "Kalender-Einstellungen konnten nicht vorbereitet werden")
+		return
+	}
+
+	rawHours, err := json.Marshal(payload.CoreWorkingHours)
+	if err != nil {
+		writeError(w, http.StatusBadRequest, "Kalender-Einstellungen sind ungültig")
+		return
+	}
+
+	_, err = s.db.Exec(
+		r.Context(),
+		`
+		INSERT INTO calendar_settings (id, core_working_hours)
+		VALUES (1, $1::JSONB)
+		ON CONFLICT (id) DO UPDATE SET
+			core_working_hours = EXCLUDED.core_working_hours,
+			updated_at = now()
+		`,
+		string(rawHours),
+	)
+	if err != nil {
+		writeError(w, http.StatusInternalServerError, "Kalender-Einstellungen konnten nicht gespeichert werden")
+		return
+	}
+
+	settings, err := s.loadCalendarSettings(r)
+	if err != nil {
+		writeError(w, http.StatusInternalServerError, "Kalender-Einstellungen wurden gespeichert, konnten aber nicht neu geladen werden")
+		return
+	}
+
+	writeJSON(w, http.StatusOK, map[string]any{
+		"message":  "Kalender-Einstellungen gespeichert",
+		"settings": settings,
+	})
+}

backend/channels.go

@@ -579,8 +579,15 @@ func (s *Server) createChannelMessage(
 	err = tx.QueryRow(
 		ctx,
 		`
-		INSERT INTO messages (conversation_id, body)
+		INSERT INTO messages (conversation_id, body, expires_at)
-		SELECT id, $2
+		SELECT
+			id,
+			$2,
+			CASE
+				WHEN disappearing_seconds > 0
+					THEN now() + make_interval(secs => disappearing_seconds)
+				ELSE NULL
+			END
 		FROM conversations
 		WHERE id = $1
 		  AND type = 'channel'

backend/chat.go

@@ -3,6 +3,7 @@ package main
 import (
 	"context"
 	"database/sql"
+	"encoding/json"
 	"errors"
 	"math"
 	"net/http"
@@ -30,9 +31,12 @@ type ChatUser struct {
 type ChatMessage struct {
 	ID                     string                `json:"id"`
 	ConversationID         string                `json:"conversationId"`
+	Type                   string                `json:"type"`
 	Body                   string                `json:"body"`
+	SystemEvent            json.RawMessage       `json:"systemEvent,omitempty"`
 	CreatedAt              time.Time             `json:"createdAt"`
 	EditedAt               *time.Time            `json:"editedAt"`
+	ExpiresAt              *time.Time            `json:"expiresAt,omitempty"`
 	Sender                 ChatUser              `json:"sender"`
 	Attachments            []ChatAttachment      `json:"attachments"`
 	ReplyTo                *ChatMessageReference `json:"replyTo"`
@@ -73,17 +77,19 @@ type ChatMessageReference struct {
 }
 
 type ChatConversation struct {
-	ID            string       `json:"id"`
+	ID                  string       `json:"id"`
-	Type          string       `json:"type"`
+	Type                string       `json:"type"`
-	Name          string       `json:"name"`
+	Name                string       `json:"name"`
-	Image         string       `json:"image"`
+	Image               string       `json:"image"`
-	TeamID        string       `json:"teamId"`
+	TeamID              string       `json:"teamId"`
-	Participants  []ChatUser   `json:"participants"`
+	OwnerID             string       `json:"ownerId"`
-	LastMessage   *ChatMessage `json:"lastMessage"`
+	DisappearingSeconds int          `json:"disappearingSeconds"`
-	LastMessageAt *time.Time   `json:"lastMessageAt"`
+	Participants        []ChatUser   `json:"participants"`
-	Muted         bool         `json:"muted"`
+	LastMessage         *ChatMessage `json:"lastMessage"`
-	UnreadCount   int          `json:"unreadCount"`
+	LastMessageAt       *time.Time   `json:"lastMessageAt"`
-	CreatedAt     time.Time    `json:"createdAt"`
+	Muted               bool         `json:"muted"`
+	UnreadCount         int          `json:"unreadCount"`
+	CreatedAt           time.Time    `json:"createdAt"`
 }
 
 type createDirectConversationRequest struct {
@@ -199,30 +205,40 @@ func (s *Server) handleListChatUsers(w http.ResponseWriter, r *http.Request) {
 	writeJSON(w, http.StatusOK, map[string]any{"users": users})
 }
 
-func (s *Server) ensureTeamConversations(ctx context.Context, userID string) error {
+func (s *Server) ensureTeamGroupConversations(ctx context.Context) error {
 	_, err := s.db.Exec(
 		ctx,
 		`
-		WITH user_team_conversations AS (
+		WITH team_groups AS (
 			INSERT INTO conversations (type, name, team_id, created_by)
-			SELECT 'team', t.name, t.id, $1
+			SELECT 'group', t.name, t.id, NULL
 			FROM teams t
-			JOIN user_teams current_membership
-				ON current_membership.team_id = t.id
-				AND current_membership.user_id = $1
 			ON CONFLICT (team_id) WHERE team_id IS NOT NULL
 			DO UPDATE SET
+				type = 'group',
 				name = EXCLUDED.name,
+				created_by = NULL,
 				updated_at = now()
 			RETURNING id, team_id
+		),
+		removed_members AS (
+			DELETE FROM conversation_members cm
+			USING conversations c
+			WHERE cm.conversation_id = c.id
+			  AND c.team_id IS NOT NULL
+			  AND NOT EXISTS (
+				SELECT 1
+				FROM user_teams ut
+				WHERE ut.team_id = c.team_id
+				  AND ut.user_id = cm.user_id
+			  )
 		)
 		INSERT INTO conversation_members (conversation_id, user_id)
-		SELECT utc.id, ut.user_id
+		SELECT tg.id, ut.user_id
-		FROM user_team_conversations utc
+		FROM team_groups tg
-		JOIN user_teams ut ON ut.team_id = utc.team_id
+		JOIN user_teams ut ON ut.team_id = tg.team_id
 		ON CONFLICT (conversation_id, user_id) DO NOTHING
 		`,
-		userID,
 	)
 
 	return err
@@ -235,8 +251,8 @@ func (s *Server) handleListChatConversations(w http.ResponseWriter, r *http.Requ
 		return
 	}
 
-	if err := s.ensureTeamConversations(r.Context(), user.ID); err != nil {
+	if err := s.ensureTeamGroupConversations(r.Context()); err != nil {
-		writeError(w, http.StatusInternalServerError, "Team-Chats konnten nicht vorbereitet werden")
+		writeError(w, http.StatusInternalServerError, "Team-Gruppenchats konnten nicht vorbereitet werden")
 		return
 	}
 	if err := s.ensureAllUserChannels(r.Context(), user.ID); err != nil {
@@ -269,29 +285,21 @@ func (s *Server) handleListChatConversations(w http.ResponseWriter, r *http.Requ
 				WHERE unread_message.conversation_id = c.id
 				  AND unread_message.deleted_at IS NULL
 				  AND unread_message.sender_id IS DISTINCT FROM $1::UUID
+				  AND (unread_message.expires_at IS NULL OR unread_message.expires_at > now())
 				  AND unread_message.created_at > COALESCE(
 					current_membership.last_read_at,
 					'-infinity'::TIMESTAMPTZ
 				  )
 			), 0),
-			c.created_at
+			c.created_at,
+			COALESCE(c.created_by::TEXT, ''),
+			c.disappearing_seconds
 		FROM conversations c
-		WHERE (
+		WHERE EXISTS (
-			c.type = 'team'
+			SELECT 1
-			AND EXISTS (
+			FROM conversation_members cm
-				SELECT 1
+			WHERE cm.conversation_id = c.id
-				FROM user_teams ut
+			  AND cm.user_id = $1
-				WHERE ut.team_id = c.team_id
-				  AND ut.user_id = $1
-			)
-		) OR (
-			c.type <> 'team'
-			AND EXISTS (
-				SELECT 1
-				FROM conversation_members cm
-				WHERE cm.conversation_id = c.id
-				  AND cm.user_id = $1
-			)
 		)
 		ORDER BY COALESCE(c.last_message_at, c.created_at) DESC
 		`,
@@ -316,6 +324,8 @@ func (s *Server) handleListChatConversations(w http.ResponseWriter, r *http.Requ
 			&conversation.Muted,
 			&conversation.UnreadCount,
 			&conversation.CreatedAt,
+			&conversation.OwnerID,
+			&conversation.DisappearingSeconds,
 		); err != nil {
 			writeError(w, http.StatusInternalServerError, "Chats konnten nicht gelesen werden")
 			return
@@ -498,12 +508,16 @@ func (s *Server) handleListChatMessages(w http.ResponseWriter, r *http.Request)
 						ELSE u.last_seen_at
 					END
 				ELSE NULL
-			END
+			END,
+			m.message_type,
+			m.system_event,
+			m.expires_at
 		FROM messages m
 		JOIN conversations c ON c.id = m.conversation_id
 		LEFT JOIN users u ON u.id = m.sender_id
 		WHERE m.conversation_id = $1
 		  AND m.deleted_at IS NULL
+		  AND (m.expires_at IS NULL OR m.expires_at > now())
 		ORDER BY m.created_at ASC, m.id ASC
 		LIMIT 200
 		`,
@@ -686,18 +700,25 @@ func (s *Server) createChatMessage(
 			forwarded_from_message_id,
 			location_lat,
 			location_lng,
-			location_label
+			location_label,
+			expires_at
 		)
-		VALUES (
+		SELECT
-			$1,
+			c.id,
 			$2,
 			$3,
 			NULLIF($4, '')::UUID,
 			NULLIF($5, '')::UUID,
 			$6,
 			$7,
-			$8
+			$8,
-		)
+			CASE
+				WHEN c.disappearing_seconds > 0
+					THEN now() + make_interval(secs => c.disappearing_seconds)
+				ELSE NULL
+			END
+		FROM conversations c
+		WHERE c.id = $1
 		RETURNING id::TEXT
 		`,
 		conversationID,
@@ -835,25 +856,11 @@ func (s *Server) canAccessConversation(ctx context.Context, conversationID strin
 			SELECT 1
 			FROM conversations c
 			WHERE c.id = $1
-			  AND (
+			  AND EXISTS (
-				(
+				SELECT 1
-					c.type = 'team'
+				FROM conversation_members cm
-					AND EXISTS (
+				WHERE cm.conversation_id = c.id
-						SELECT 1
+				  AND cm.user_id = $2
-						FROM user_teams ut
-						WHERE ut.team_id = c.team_id
-						  AND ut.user_id = $2
-					)
-				)
-				OR (
-					c.type <> 'team'
-					AND EXISTS (
-						SELECT 1
-						FROM conversation_members cm
-						WHERE cm.conversation_id = c.id
-						  AND cm.user_id = $2
-					)
-				)
 			  )
 		)
 		`,
@@ -923,26 +930,8 @@ func (s *Server) listChatParticipants(ctx context.Context, conversationID string
 				ELSE NULL
 			END
 		FROM conversations c
-		JOIN users u ON (
+		JOIN conversation_members cm ON cm.conversation_id = c.id
-			(
+		JOIN users u ON u.id = cm.user_id
-				c.type = 'team'
-				AND EXISTS (
-					SELECT 1
-					FROM user_teams ut
-					WHERE ut.team_id = c.team_id
-					  AND ut.user_id = u.id
-				)
-			)
-			OR (
-				c.type <> 'team'
-				AND EXISTS (
-					SELECT 1
-					FROM conversation_members cm
-					WHERE cm.conversation_id = c.id
-					  AND cm.user_id = u.id
-				)
-			)
-		)
 		WHERE c.id = $1
 		ORDER BY lower(COALESCE(NULLIF(u.display_name, ''), u.username, u.email))
 		`,
@@ -1014,12 +1003,15 @@ func (s *Server) getChatConversation(ctx context.Context, conversationID string,
 				WHERE unread_message.conversation_id = c.id
 				  AND unread_message.deleted_at IS NULL
 				  AND unread_message.sender_id IS DISTINCT FROM $2::UUID
+				  AND (unread_message.expires_at IS NULL OR unread_message.expires_at > now())
 				  AND unread_message.created_at > COALESCE(
 					current_membership.last_read_at,
 					'-infinity'::TIMESTAMPTZ
 				  )
 			), 0),
-			c.created_at
+			c.created_at,
+			COALESCE(c.created_by::TEXT, ''),
+			c.disappearing_seconds
 		FROM conversations c
 		WHERE c.id = $1
 		`,
@@ -1035,6 +1027,8 @@ func (s *Server) getChatConversation(ctx context.Context, conversationID string,
 		&conversation.Muted,
 		&conversation.UnreadCount,
 		&conversation.CreatedAt,
+		&conversation.OwnerID,
+		&conversation.DisappearingSeconds,
 	)
 	if err != nil {
 		return conversation, err
@@ -1082,6 +1076,9 @@ func scanChatMessage(scanner chatMessageScanner) (ChatMessage, error) {
 		&message.Sender.LastSeenAt,
 		&message.Sender.AwaySince,
 		&message.Sender.LastOnlineAt,
+		&message.Type,
+		&message.SystemEvent,
+		&message.ExpiresAt,
 	)
 	message.Sender.Online = message.Sender.PresenceStatus == "online"
 	return message, err
@@ -1137,7 +1134,10 @@ func (s *Server) getChatMessage(ctx context.Context, messageID string) (ChatMess
 						ELSE u.last_seen_at
 					END
 				ELSE NULL
-			END
+			END,
+			m.message_type,
+			m.system_event,
+			m.expires_at
 		FROM messages m
 		JOIN conversations c ON c.id = m.conversation_id
 		LEFT JOIN users u ON u.id = m.sender_id
@@ -1203,12 +1203,16 @@ func (s *Server) getLastChatMessage(ctx context.Context, conversationID string)
 						ELSE u.last_seen_at
 					END
 				ELSE NULL
-			END
+			END,
+			m.message_type,
+			m.system_event,
+			m.expires_at
 		FROM messages m
 		JOIN conversations c ON c.id = m.conversation_id
 		LEFT JOIN users u ON u.id = m.sender_id
 		WHERE m.conversation_id = $1
 		  AND m.deleted_at IS NULL
+		  AND (m.expires_at IS NULL OR m.expires_at > now())
 		ORDER BY m.created_at DESC, m.id DESC
 		LIMIT 1
 		`,

backend/chat_groups.go

@@ -0,0 +1,850 @@
+// backend/chat_groups.go
+//
+// Gruppenchats (Typ 'group') sowie selbstlöschende Nachrichten und die daraus
+// resultierenden System-Nachrichten. Gruppen werden ausschließlich vom
+// Ersteller/Owner (conversations.created_by) verwaltet.
+
+package main
+
+import (
+	"context"
+	"encoding/json"
+	"errors"
+	"fmt"
+	"net/http"
+	"strings"
+	"time"
+
+	"github.com/jackc/pgx/v5"
+)
+
+const (
+	maxGroupNameLength = 80
+	maxGroupImageBytes = 3 * 1024 * 1024
+)
+
+// Erlaubte Selbstlösch-Zeiträume in Sekunden: Aus, 1 Stunde, 1 Tag, 1 Woche.
+var allowedDisappearingSeconds = map[int]bool{
+	0:      true,
+	3600:   true,
+	86400:  true,
+	604800: true,
+}
+
+type createGroupRequest struct {
+	Name      string   `json:"name"`
+	Image     string   `json:"image"`
+	MemberIDs []string `json:"memberIds"`
+}
+
+type updateGroupRequest struct {
+	Name  *string `json:"name"`
+	Image *string `json:"image"`
+}
+
+type addGroupMembersRequest struct {
+	UserIDs []string `json:"userIds"`
+}
+
+type updateDisappearingRequest struct {
+	Seconds int `json:"seconds"`
+}
+
+func conversationActorName(u User) string {
+	if name := strings.TrimSpace(u.DisplayName); name != "" {
+		return name
+	}
+	if name := strings.TrimSpace(u.Username); name != "" {
+		return name
+	}
+	return u.Email
+}
+
+func disappearingDurationLabel(seconds int) string {
+	switch seconds {
+	case 3600:
+		return "1 Stunde"
+	case 86400:
+		return "1 Tag"
+	case 604800:
+		return "1 Woche"
+	default:
+		return ""
+	}
+}
+
+// startDisappearingMessagesMonitor löscht periodisch abgelaufene
+// selbstlöschende Nachrichten (Anhänge werden per FK ON DELETE CASCADE entfernt).
+func (s *Server) startDisappearingMessagesMonitor(ctx context.Context) {
+	s.reconcileDisappearingMessages(ctx)
+
+	go func() {
+		ticker := time.NewTicker(60 * time.Second)
+		defer ticker.Stop()
+
+		for {
+			select {
+			case <-ctx.Done():
+				return
+			case <-ticker.C:
+				s.reconcileDisappearingMessages(ctx)
+			}
+		}
+	}()
+}
+
+func (s *Server) reconcileDisappearingMessages(ctx context.Context) {
+	if _, err := s.db.Exec(
+		ctx,
+		`UPDATE messages AS m
+		 SET expires_at = m.created_at + make_interval(secs => c.disappearing_seconds)
+		 FROM conversations AS c
+		 WHERE m.conversation_id = c.id
+		   AND c.disappearing_seconds > 0
+		   AND m.message_type = 'user'
+		   AND m.deleted_at IS NULL
+		   AND m.expires_at IS NULL`,
+	); err != nil {
+		logError("Ablaufzeiten selbstlöschender Nachrichten konnten nicht ergänzt werden", err, nil)
+		return
+	}
+
+	s.deleteExpiredMessages(ctx)
+}
+
+func (s *Server) deleteExpiredMessages(ctx context.Context) {
+	if _, err := s.db.Exec(
+		ctx,
+		`DELETE FROM messages WHERE expires_at IS NOT NULL AND expires_at <= now()`,
+	); err != nil {
+		logError("Abgelaufene Nachrichten konnten nicht gelöscht werden", err, nil)
+	}
+}
+
+func canManageGroup(user User, ownerID string) bool {
+	return ownerID == user.ID || userHasRight(user, "admin")
+}
+
+func canManageTeamGroup(user User) bool {
+	return userHasRight(user, "teams:write")
+}
+
+func (s *Server) canManageGroupConversation(ctx context.Context, conversationID string, user User) bool {
+	if strings.TrimSpace(conversationID) == "" || strings.TrimSpace(user.ID) == "" {
+		return false
+	}
+
+	var ownerID string
+	err := s.db.QueryRow(
+		ctx,
+		`
+		SELECT COALESCE(created_by::TEXT, '')
+		FROM conversations
+		WHERE id = $1
+		  AND type = 'group'
+		  AND team_id IS NULL
+		`,
+		conversationID,
+	).Scan(&ownerID)
+
+	return err == nil && canManageGroup(user, ownerID)
+}
+
+func (s *Server) userDisplayName(ctx context.Context, userID string) string {
+	var name string
+	err := s.db.QueryRow(
+		ctx,
+		`SELECT COALESCE(NULLIF(display_name, ''), NULLIF(username, ''), email, 'Unbekannt') FROM users WHERE id = $1`,
+		userID,
+	).Scan(&name)
+	if err != nil || strings.TrimSpace(name) == "" {
+		return "Unbekannt"
+	}
+	return name
+}
+
+// createSystemMessage legt eine nicht ablaufende System-Nachricht im Verlauf an.
+func (s *Server) createSystemMessage(
+	ctx context.Context,
+	conversationID string,
+	actorID string,
+	event string,
+	body string,
+	data map[string]any,
+) (ChatMessage, error) {
+	payload := map[string]any{"event": event}
+	for key, value := range data {
+		payload[key] = value
+	}
+
+	eventJSON, err := json.Marshal(payload)
+	if err != nil {
+		return ChatMessage{}, err
+	}
+
+	var messageID string
+	err = s.db.QueryRow(
+		ctx,
+		`
+		INSERT INTO messages (conversation_id, sender_id, body, message_type, system_event)
+		VALUES ($1, NULLIF($2, '')::UUID, $3, 'system', $4::JSONB)
+		RETURNING id::TEXT
+		`,
+		conversationID,
+		actorID,
+		body,
+		string(eventJSON),
+	).Scan(&messageID)
+	if err != nil {
+		return ChatMessage{}, err
+	}
+
+	if _, err := s.db.Exec(
+		ctx,
+		`UPDATE conversations SET last_message_at = now(), updated_at = now() WHERE id = $1`,
+		conversationID,
+	); err != nil {
+		return ChatMessage{}, err
+	}
+
+	return s.getChatMessage(ctx, messageID)
+}
+
+// emitSystemMessage erzeugt eine System-Nachricht und verteilt sie an alle
+// Mitglieder (ohne Web-Push, siehe publishChatMessage).
+func (s *Server) emitSystemMessage(
+	ctx context.Context,
+	conversationID string,
+	actorID string,
+	event string,
+	body string,
+	data map[string]any,
+) {
+	message, err := s.createSystemMessage(ctx, conversationID, actorID, event, body, data)
+	if err != nil {
+		return
+	}
+	s.publishChatMessage(ctx, message, "")
+}
+
+func (s *Server) handleCreateGroup(w http.ResponseWriter, r *http.Request) {
+	user, ok := userFromContext(r.Context())
+	if !ok {
+		writeError(w, http.StatusUnauthorized, "Unauthorized")
+		return
+	}
+
+	var input createGroupRequest
+	if err := readJSON(r, &input); err != nil {
+		writeError(w, http.StatusBadRequest, "Ungültige Anfrage")
+		return
+	}
+
+	name := strings.TrimSpace(input.Name)
+	if name == "" || len([]rune(name)) > maxGroupNameLength {
+		writeError(w, http.StatusBadRequest, "Gruppenname muss 1–80 Zeichen lang sein")
+		return
+	}
+	image := strings.TrimSpace(input.Image)
+	if len(image) > maxGroupImageBytes {
+		writeError(w, http.StatusBadRequest, "Das Gruppenbild ist zu groß")
+		return
+	}
+
+	memberIDs := map[string]struct{}{user.ID: {}}
+	for _, id := range input.MemberIDs {
+		if id = strings.TrimSpace(id); id != "" {
+			memberIDs[id] = struct{}{}
+		}
+	}
+
+	tx, err := s.db.Begin(r.Context())
+	if err != nil {
+		writeError(w, http.StatusInternalServerError, "Gruppe konnte nicht erstellt werden")
+		return
+	}
+	defer tx.Rollback(r.Context())
+
+	var conversationID string
+	err = tx.QueryRow(
+		r.Context(),
+		`
+		INSERT INTO conversations (type, name, channel_image, created_by)
+		VALUES ('group', $1, $2, $3)
+		RETURNING id::TEXT
+		`,
+		name,
+		image,
+		user.ID,
+	).Scan(&conversationID)
+	if err != nil {
+		writeError(w, http.StatusInternalServerError, "Gruppe konnte nicht erstellt werden")
+		return
+	}
+
+	for id := range memberIDs {
+		if _, err := tx.Exec(
+			r.Context(),
+			`
+			INSERT INTO conversation_members (conversation_id, user_id)
+			SELECT $1, id FROM users WHERE id = $2
+			ON CONFLICT (conversation_id, user_id) DO NOTHING
+			`,
+			conversationID,
+			id,
+		); err != nil {
+			writeError(w, http.StatusInternalServerError, "Gruppenmitglieder konnten nicht gespeichert werden")
+			return
+		}
+	}
+
+	if err := tx.Commit(r.Context()); err != nil {
+		writeError(w, http.StatusInternalServerError, "Gruppe konnte nicht gespeichert werden")
+		return
+	}
+
+	// Erst die Konversation an alle Mitglieder verteilen (damit der Chat in der
+	// Seitenleiste erscheint), dann die "erstellt"-System-Nachricht senden.
+	s.publishConversationUpdate(r.Context(), conversationID)
+	s.emitSystemMessage(
+		r.Context(),
+		conversationID,
+		user.ID,
+		"group_created",
+		fmt.Sprintf("%s hat die Gruppe erstellt.", conversationActorName(user)),
+		nil,
+	)
+
+	conversation, err := s.getChatConversation(r.Context(), conversationID, user.ID, user.ShowLastSeen)
+	if err != nil {
+		writeError(w, http.StatusInternalServerError, "Gruppe konnte nicht geladen werden")
+		return
+	}
+
+	writeJSON(w, http.StatusCreated, map[string]any{"conversation": conversation})
+}
+
+func (s *Server) handleUpdateGroup(w http.ResponseWriter, r *http.Request) {
+	user, ok := userFromContext(r.Context())
+	if !ok {
+		writeError(w, http.StatusUnauthorized, "Unauthorized")
+		return
+	}
+
+	conversationID := strings.TrimSpace(r.PathValue("id"))
+
+	var input updateGroupRequest
+	if err := readJSON(r, &input); err != nil {
+		writeError(w, http.StatusBadRequest, "Ungültige Anfrage")
+		return
+	}
+
+	var currentName, currentImage, ownerID, teamID string
+	if err := s.db.QueryRow(
+		r.Context(),
+		`
+		SELECT
+			name,
+			channel_image,
+			COALESCE(created_by::TEXT, ''),
+			COALESCE(team_id::TEXT, '')
+		FROM conversations
+		WHERE id = $1
+		  AND type = 'group'
+		`,
+		conversationID,
+	).Scan(&currentName, &currentImage, &ownerID, &teamID); err != nil {
+		writeError(w, http.StatusNotFound, "Gruppe wurde nicht gefunden")
+		return
+	}
+
+	if teamID != "" {
+		if !canManageTeamGroup(user) {
+			writeError(w, http.StatusForbidden, "Keine Berechtigung zum Verwalten des Team-Gruppenchats")
+			return
+		}
+		if input.Name != nil {
+			writeError(w, http.StatusBadRequest, "Der Name des Team-Gruppenchats wird über das Team verwaltet")
+			return
+		}
+	} else if !canManageGroup(user, ownerID) {
+		writeError(w, http.StatusForbidden, "Nur der Ersteller oder ein Administrator darf die Gruppe verwalten")
+		return
+	}
+
+	changed := false
+
+	if input.Name != nil {
+		newName := strings.TrimSpace(*input.Name)
+		if newName == "" || len([]rune(newName)) > maxGroupNameLength {
+			writeError(w, http.StatusBadRequest, "Gruppenname muss 1–80 Zeichen lang sein")
+			return
+		}
+		if newName != currentName {
+			if _, err := s.db.Exec(
+				r.Context(),
+				`UPDATE conversations SET name = $2, updated_at = now() WHERE id = $1`,
+				conversationID,
+				newName,
+			); err != nil {
+				writeError(w, http.StatusInternalServerError, "Gruppe konnte nicht aktualisiert werden")
+				return
+			}
+			s.emitSystemMessage(
+				r.Context(),
+				conversationID,
+				user.ID,
+				"group_renamed",
+				fmt.Sprintf("%s hat die Gruppe in „%s“ umbenannt.", conversationActorName(user), newName),
+				map[string]any{"name": newName},
+			)
+			changed = true
+		}
+	}
+
+	if input.Image != nil {
+		newImage := strings.TrimSpace(*input.Image)
+		if len(newImage) > maxGroupImageBytes {
+			writeError(w, http.StatusBadRequest, "Das Gruppenbild ist zu groß")
+			return
+		}
+		if newImage != currentImage {
+			if _, err := s.db.Exec(
+				r.Context(),
+				`UPDATE conversations SET channel_image = $2, updated_at = now() WHERE id = $1`,
+				conversationID,
+				newImage,
+			); err != nil {
+				writeError(w, http.StatusInternalServerError, "Gruppe konnte nicht aktualisiert werden")
+				return
+			}
+			s.emitSystemMessage(
+				r.Context(),
+				conversationID,
+				user.ID,
+				"group_image_changed",
+				fmt.Sprintf("%s hat das Gruppenbild geändert.", conversationActorName(user)),
+				nil,
+			)
+			changed = true
+		}
+	}
+
+	if changed {
+		s.publishConversationUpdate(r.Context(), conversationID)
+	}
+
+	conversation, err := s.getChatConversation(r.Context(), conversationID, user.ID, user.ShowLastSeen)
+	if err != nil {
+		writeError(w, http.StatusInternalServerError, "Gruppe konnte nicht geladen werden")
+		return
+	}
+
+	writeJSON(w, http.StatusOK, map[string]any{"conversation": conversation})
+}
+
+func (s *Server) handleAddGroupMembers(w http.ResponseWriter, r *http.Request) {
+	user, ok := userFromContext(r.Context())
+	if !ok {
+		writeError(w, http.StatusUnauthorized, "Unauthorized")
+		return
+	}
+
+	conversationID := strings.TrimSpace(r.PathValue("id"))
+	if !s.canManageGroupConversation(r.Context(), conversationID, user) {
+		writeError(w, http.StatusForbidden, "Nur der Ersteller oder ein Administrator darf die Gruppe verwalten")
+		return
+	}
+
+	var input addGroupMembersRequest
+	if err := readJSON(r, &input); err != nil {
+		writeError(w, http.StatusBadRequest, "Ungültige Anfrage")
+		return
+	}
+
+	added := false
+	seen := map[string]struct{}{}
+	for _, rawID := range input.UserIDs {
+		id := strings.TrimSpace(rawID)
+		if id == "" {
+			continue
+		}
+		if _, dup := seen[id]; dup {
+			continue
+		}
+		seen[id] = struct{}{}
+
+		commandTag, err := s.db.Exec(
+			r.Context(),
+			`
+			INSERT INTO conversation_members (conversation_id, user_id)
+			SELECT $1, id FROM users WHERE id = $2
+			ON CONFLICT (conversation_id, user_id) DO NOTHING
+			`,
+			conversationID,
+			id,
+		)
+		if err != nil {
+			writeError(w, http.StatusInternalServerError, "Mitglied konnte nicht hinzugefügt werden")
+			return
+		}
+		if commandTag.RowsAffected() == 0 {
+			continue
+		}
+
+		s.emitSystemMessage(
+			r.Context(),
+			conversationID,
+			user.ID,
+			"member_added",
+			fmt.Sprintf("%s hat %s hinzugefügt.", conversationActorName(user), s.userDisplayName(r.Context(), id)),
+			map[string]any{"targetUserId": id},
+		)
+		added = true
+	}
+
+	if added {
+		s.publishConversationUpdate(r.Context(), conversationID)
+	}
+
+	conversation, err := s.getChatConversation(r.Context(), conversationID, user.ID, user.ShowLastSeen)
+	if err != nil {
+		writeError(w, http.StatusInternalServerError, "Gruppe konnte nicht geladen werden")
+		return
+	}
+
+	writeJSON(w, http.StatusOK, map[string]any{"conversation": conversation})
+}
+
+func (s *Server) handleRemoveGroupMember(w http.ResponseWriter, r *http.Request) {
+	user, ok := userFromContext(r.Context())
+	if !ok {
+		writeError(w, http.StatusUnauthorized, "Unauthorized")
+		return
+	}
+
+	conversationID := strings.TrimSpace(r.PathValue("id"))
+	targetID := strings.TrimSpace(r.PathValue("userId"))
+
+	var convType, ownerID, teamID string
+	err := s.db.QueryRow(
+		r.Context(),
+		`
+		SELECT type, COALESCE(created_by::TEXT, ''), COALESCE(team_id::TEXT, '')
+		FROM conversations
+		WHERE id = $1
+		`,
+		conversationID,
+	).Scan(&convType, &ownerID, &teamID)
+	if errors.Is(err, pgx.ErrNoRows) || convType != "group" || teamID != "" {
+		writeError(w, http.StatusNotFound, "Gruppe wurde nicht gefunden")
+		return
+	}
+	if err != nil {
+		writeError(w, http.StatusInternalServerError, "Gruppe konnte nicht geladen werden")
+		return
+	}
+
+	isManager := canManageGroup(user, ownerID)
+	isSelf := targetID == user.ID
+	if !isManager && !isSelf {
+		writeError(w, http.StatusForbidden, "Nur der Ersteller oder ein Administrator darf Mitglieder entfernen")
+		return
+	}
+	if targetID == ownerID {
+		writeError(w, http.StatusBadRequest, "Der Ersteller kann die Gruppe nicht verlassen")
+		return
+	}
+
+	commandTag, err := s.db.Exec(
+		r.Context(),
+		`DELETE FROM conversation_members WHERE conversation_id = $1 AND user_id = $2`,
+		conversationID,
+		targetID,
+	)
+	if err != nil {
+		writeError(w, http.StatusInternalServerError, "Mitglied konnte nicht entfernt werden")
+		return
+	}
+	if commandTag.RowsAffected() == 0 {
+		writeError(w, http.StatusNotFound, "Mitglied wurde nicht gefunden")
+		return
+	}
+
+	if isSelf {
+		s.emitSystemMessage(
+			r.Context(),
+			conversationID,
+			targetID,
+			"member_left",
+			fmt.Sprintf("%s hat die Gruppe verlassen.", conversationActorName(user)),
+			nil,
+		)
+	} else {
+		s.emitSystemMessage(
+			r.Context(),
+			conversationID,
+			user.ID,
+			"member_removed",
+			fmt.Sprintf("%s hat %s entfernt.", conversationActorName(user), s.userDisplayName(r.Context(), targetID)),
+			map[string]any{"targetUserId": targetID},
+		)
+	}
+
+	// Verbleibende Mitglieder erhalten die aktualisierte Mitgliederliste, der
+	// entfernte Nutzer erhält einen Hinweis, den Chat zu entfernen.
+	s.publishConversationUpdate(r.Context(), conversationID)
+	chatSockets.publish(targetID, chatSocketEvent{
+		Type:           "conversation.removed",
+		ConversationID: conversationID,
+	})
+
+	writeJSON(w, http.StatusOK, map[string]bool{"ok": true})
+}
+
+func (s *Server) handleDeleteGroup(w http.ResponseWriter, r *http.Request) {
+	user, ok := userFromContext(r.Context())
+	if !ok {
+		writeError(w, http.StatusUnauthorized, "Unauthorized")
+		return
+	}
+
+	conversationID := strings.TrimSpace(r.PathValue("id"))
+
+	var conversationType, ownerID, teamID string
+	err := s.db.QueryRow(
+		r.Context(),
+		`
+		SELECT type, COALESCE(created_by::TEXT, ''), COALESCE(team_id::TEXT, '')
+		FROM conversations
+		WHERE id = $1
+		`,
+		conversationID,
+	).Scan(&conversationType, &ownerID, &teamID)
+	if errors.Is(err, pgx.ErrNoRows) || conversationType != "group" || teamID != "" {
+		writeError(w, http.StatusNotFound, "Gruppe wurde nicht gefunden")
+		return
+	}
+	if err != nil {
+		writeError(w, http.StatusInternalServerError, "Gruppe konnte nicht geladen werden")
+		return
+	}
+	if !canManageGroup(user, ownerID) {
+		writeError(w, http.StatusForbidden, "Nur der Ersteller oder ein Administrator darf die Gruppe löschen")
+		return
+	}
+
+	memberIDs, err := s.chatConversationMemberIDs(r.Context(), conversationID)
+	if err != nil {
+		writeError(w, http.StatusInternalServerError, "Gruppenmitglieder konnten nicht geladen werden")
+		return
+	}
+
+	tx, err := s.db.Begin(r.Context())
+	if err != nil {
+		writeError(w, http.StatusInternalServerError, "Gruppe konnte nicht gelöscht werden")
+		return
+	}
+	defer tx.Rollback(r.Context())
+
+	if _, err := tx.Exec(
+		r.Context(),
+		`DELETE FROM notifications WHERE entity_type = 'chat' AND entity_id = $1`,
+		conversationID,
+	); err != nil {
+		writeError(w, http.StatusInternalServerError, "Chat-Benachrichtigungen konnten nicht gelöscht werden")
+		return
+	}
+
+	commandTag, err := tx.Exec(
+		r.Context(),
+		`DELETE FROM conversations WHERE id = $1 AND type = 'group' AND team_id IS NULL`,
+		conversationID,
+	)
+	if err != nil {
+		writeError(w, http.StatusInternalServerError, "Gruppe konnte nicht gelöscht werden")
+		return
+	}
+	if commandTag.RowsAffected() == 0 {
+		writeError(w, http.StatusNotFound, "Gruppe wurde nicht gefunden")
+		return
+	}
+
+	if err := tx.Commit(r.Context()); err != nil {
+		writeError(w, http.StatusInternalServerError, "Gruppe konnte nicht gelöscht werden")
+		return
+	}
+
+	for _, memberID := range memberIDs {
+		chatSockets.publish(memberID, chatSocketEvent{
+			Type:           "conversation.removed",
+			ConversationID: conversationID,
+		})
+	}
+
+	writeJSON(w, http.StatusOK, map[string]bool{"ok": true})
+}
+
+func (s *Server) handleUpdateDisappearing(w http.ResponseWriter, r *http.Request) {
+	user, ok := userFromContext(r.Context())
+	if !ok {
+		writeError(w, http.StatusUnauthorized, "Unauthorized")
+		return
+	}
+
+	conversationID := strings.TrimSpace(r.PathValue("id"))
+
+	var input updateDisappearingRequest
+	if err := readJSON(r, &input); err != nil {
+		writeError(w, http.StatusBadRequest, "Ungültige Anfrage")
+		return
+	}
+	if !allowedDisappearingSeconds[input.Seconds] {
+		writeError(w, http.StatusBadRequest, "Ungültiger Zeitraum")
+		return
+	}
+
+	var convType, ownerID, teamID string
+	err := s.db.QueryRow(
+		r.Context(),
+		`
+		SELECT type, COALESCE(created_by::TEXT, ''), COALESCE(team_id::TEXT, '')
+		FROM conversations
+		WHERE id = $1
+		`,
+		conversationID,
+	).Scan(&convType, &ownerID, &teamID)
+	if errors.Is(err, pgx.ErrNoRows) {
+		writeError(w, http.StatusNotFound, "Chat wurde nicht gefunden")
+		return
+	}
+	if err != nil {
+		writeError(w, http.StatusInternalServerError, "Chat konnte nicht geladen werden")
+		return
+	}
+
+	switch convType {
+	case "direct":
+		if !s.canAccessConversation(r.Context(), conversationID, user.ID) {
+			writeError(w, http.StatusForbidden, "Kein Zugriff auf diesen Chat")
+			return
+		}
+	case "group":
+		if teamID != "" {
+			if !canManageTeamGroup(user) {
+				writeError(w, http.StatusForbidden, "Keine Berechtigung zum Ändern selbstlöschender Nachrichten im Team-Gruppenchat")
+				return
+			}
+		} else if !canManageGroup(user, ownerID) {
+			writeError(w, http.StatusForbidden, "Nur der Ersteller oder ein Administrator darf das Selbstlöschen ändern")
+			return
+		}
+	case "channel":
+		if !userHasRight(user, "admin") {
+			writeError(w, http.StatusForbidden, "Nur Administratoren dürfen das Selbstlöschen für Channels ändern")
+			return
+		}
+	default:
+		writeError(w, http.StatusBadRequest, "Selbstlöschen wird für diesen Chat nicht unterstützt")
+		return
+	}
+
+	tx, err := s.db.Begin(r.Context())
+	if err != nil {
+		writeError(w, http.StatusInternalServerError, "Einstellung konnte nicht gespeichert werden")
+		return
+	}
+	defer tx.Rollback(r.Context())
+
+	if _, err := tx.Exec(
+		r.Context(),
+		`UPDATE conversations SET disappearing_seconds = $2, updated_at = now() WHERE id = $1`,
+		conversationID,
+		input.Seconds,
+	); err != nil {
+		writeError(w, http.StatusInternalServerError, "Einstellung konnte nicht gespeichert werden")
+		return
+	}
+
+	if input.Seconds == 0 {
+		if _, err := tx.Exec(
+			r.Context(),
+			`UPDATE messages
+			 SET expires_at = NULL
+			 WHERE conversation_id = $1
+			   AND message_type = 'user'
+			   AND deleted_at IS NULL`,
+			conversationID,
+		); err != nil {
+			writeError(w, http.StatusInternalServerError, "Einstellung konnte nicht gespeichert werden")
+			return
+		}
+	} else {
+		if _, err := tx.Exec(
+			r.Context(),
+			`UPDATE messages
+			 SET expires_at = created_at + make_interval(secs => $2)
+			 WHERE conversation_id = $1
+			   AND message_type = 'user'
+			   AND deleted_at IS NULL`,
+			conversationID,
+			input.Seconds,
+		); err != nil {
+			writeError(w, http.StatusInternalServerError, "Einstellung konnte nicht gespeichert werden")
+			return
+		}
+
+		if _, err := tx.Exec(
+			r.Context(),
+			`DELETE FROM messages
+			 WHERE conversation_id = $1
+			   AND message_type = 'user'
+			   AND deleted_at IS NULL
+			   AND expires_at <= now()`,
+			conversationID,
+		); err != nil {
+			writeError(w, http.StatusInternalServerError, "Einstellung konnte nicht gespeichert werden")
+			return
+		}
+	}
+
+	if err := tx.Commit(r.Context()); err != nil {
+		writeError(w, http.StatusInternalServerError, "Einstellung konnte nicht gespeichert werden")
+		return
+	}
+
+	if input.Seconds == 0 {
+		s.emitSystemMessage(
+			r.Context(),
+			conversationID,
+			user.ID,
+			"self_delete_disabled",
+			fmt.Sprintf("%s hat selbstlöschende Nachrichten deaktiviert.", conversationActorName(user)),
+			map[string]any{"seconds": 0},
+		)
+	} else {
+		s.emitSystemMessage(
+			r.Context(),
+			conversationID,
+			user.ID,
+			"self_delete_enabled",
+			fmt.Sprintf(
+				"%s hat selbstlöschende Nachrichten aktiviert (%s).",
+				conversationActorName(user),
+				disappearingDurationLabel(input.Seconds),
+			),
+			map[string]any{"seconds": input.Seconds},
+		)
+	}
+
+	s.publishConversationUpdate(r.Context(), conversationID)
+	s.publishChatMessagesReload(r.Context(), conversationID)
+
+	conversation, err := s.getChatConversation(r.Context(), conversationID, user.ID, user.ShowLastSeen)
+	if err != nil {
+		writeError(w, http.StatusInternalServerError, "Chat konnte nicht geladen werden")
+		return
+	}
+
+	writeJSON(w, http.StatusOK, map[string]any{"conversation": conversation})
+}

backend/chat_search.go

@@ -49,26 +49,14 @@ func (s *Server) handleSearchChatMessages(w http.ResponseWriter, r *http.Request
 		JOIN conversations c ON c.id = m.conversation_id
 		LEFT JOIN users u ON u.id = m.sender_id
 		WHERE m.deleted_at IS NULL
+		  AND m.message_type = 'user'
+		  AND (m.expires_at IS NULL OR m.expires_at > now())
 		  AND strpos(lower(m.body), lower($2)) > 0
-		  AND (
+		  AND EXISTS (
-			(
+			SELECT 1
-				c.type = 'team'
+			FROM conversation_members cm
-				AND EXISTS (
+			WHERE cm.conversation_id = c.id
-					SELECT 1
+			  AND cm.user_id = $1
-					FROM user_teams ut
-					WHERE ut.team_id = c.team_id
-					  AND ut.user_id = $1
-				)
-			)
-			OR (
-				c.type <> 'team'
-				AND EXISTS (
-					SELECT 1
-					FROM conversation_members cm
-					WHERE cm.conversation_id = c.id
-					  AND cm.user_id = $1
-				)
-			)
 		  )
 		ORDER BY m.conversation_id, m.created_at DESC, m.id DESC
 		LIMIT 50

backend/chat_unread.go

@@ -41,23 +41,10 @@ func (s *Server) getChatUnreadCount(ctx context.Context, userID string) (int, er
 			ON cm.conversation_id = c.id
 			AND cm.user_id = $1
 		WHERE m.deleted_at IS NULL
+		  AND (m.expires_at IS NULL OR m.expires_at > now())
 		  AND m.sender_id IS DISTINCT FROM $1::UUID
 		  AND m.created_at > COALESCE(cm.last_read_at, '-infinity'::TIMESTAMPTZ)
-		  AND (
+		  AND cm.user_id IS NOT NULL
-			(
-				c.type = 'team'
-				AND EXISTS (
-					SELECT 1
-					FROM user_teams ut
-					WHERE ut.team_id = c.team_id
-					  AND ut.user_id = $1
-				)
-			)
-			OR (
-				c.type <> 'team'
-				AND cm.user_id IS NOT NULL
-			)
-		  )
 		`,
 		userID,
 	).Scan(&unreadCount)
@@ -71,8 +58,8 @@ func (s *Server) handleGetChatUnreadCount(w http.ResponseWriter, r *http.Request
 		return
 	}
 
-	if err := s.ensureTeamConversations(r.Context(), user.ID); err != nil {
+	if err := s.ensureTeamGroupConversations(r.Context()); err != nil {
-		writeError(w, http.StatusInternalServerError, "Team-Chats konnten nicht vorbereitet werden")
+		writeError(w, http.StatusInternalServerError, "Team-Gruppenchats konnten nicht vorbereitet werden")
 		return
 	}
 	if err := s.ensureAllUserChannels(r.Context(), user.ID); err != nil {

backend/chat_websocket.go

@@ -25,14 +25,15 @@ type chatSocketCommand struct {
 }
 
 type chatSocketEvent struct {
-	Type            string       `json:"type"`
+	Type            string            `json:"type"`
-	ClientID        string       `json:"clientId,omitempty"`
+	ClientID        string            `json:"clientId,omitempty"`
-	ConversationID  string       `json:"conversationId,omitempty"`
+	ConversationID  string            `json:"conversationId,omitempty"`
-	UserID          string       `json:"userId,omitempty"`
+	UserID          string            `json:"userId,omitempty"`
-	UserDisplayName string       `json:"userDisplayName,omitempty"`
+	UserDisplayName string            `json:"userDisplayName,omitempty"`
-	Typing          bool         `json:"typing,omitempty"`
+	Typing          bool              `json:"typing,omitempty"`
-	Message         *ChatMessage `json:"message,omitempty"`
+	Message         *ChatMessage      `json:"message,omitempty"`
-	Error           string       `json:"error,omitempty"`
+	Conversation    *ChatConversation `json:"conversation,omitempty"`
+	Error           string            `json:"error,omitempty"`
 }
 
 type chatSocketClient struct {
@@ -284,17 +285,7 @@ func (s *Server) publishChatMessage(
 		`
 		SELECT cm.user_id::TEXT, cm.muted
 		FROM conversation_members cm
-		JOIN conversations c ON c.id = cm.conversation_id
 		WHERE cm.conversation_id = $1
-		  AND (
-			c.type <> 'team'
-			OR EXISTS (
-				SELECT 1
-				FROM user_teams ut
-				WHERE ut.team_id = c.team_id
-				  AND ut.user_id = cm.user_id
-			)
-		  )
 		`,
 		message.ConversationID,
 	)
@@ -325,7 +316,13 @@ func (s *Server) publishChatMessage(
 
 	rows.Close()
 
-	title, conversationType, err := s.chatNotificationTitle(ctx, message)
+	// System-Nachrichten (Gruppen-Ereignisse, Selbstlöschen) erscheinen im
+	// Verlauf, lösen aber keine Benachrichtigung / Web-Push aus.
+	if message.Type == "system" {
+		return
+	}
+
+	title, conversationType, conversationImage, err := s.chatNotificationTitle(ctx, message)
 	if err != nil {
 		return
 	}
@@ -340,12 +337,13 @@ func (s *Server) publishChatMessage(
 	}
 
 	data, err := json.Marshal(map[string]any{
-		"conversationId":   message.ConversationID,
+		"conversationId":    message.ConversationID,
-		"messageId":        message.ID,
+		"messageId":         message.ID,
-		"senderId":         message.Sender.ID,
+		"senderId":          message.Sender.ID,
-		"senderAvatar":     message.Sender.Avatar,
+		"senderAvatar":      message.Sender.Avatar,
-		"senderName":       chatUserDisplayName(message.Sender),
+		"senderName":        chatUserDisplayName(message.Sender),
-		"conversationType": conversationType,
+		"conversationType":  conversationType,
+		"conversationImage": conversationImage,
 	})
 	if err != nil {
 		return
@@ -379,17 +377,7 @@ func (s *Server) chatConversationMemberIDs(ctx context.Context, conversationID s
 		`
 		SELECT cm.user_id::TEXT
 		FROM conversation_members cm
-		JOIN conversations c ON c.id = cm.conversation_id
 		WHERE cm.conversation_id = $1
-		  AND (
-			c.type <> 'team'
-			OR EXISTS (
-				SELECT 1
-				FROM user_teams ut
-				WHERE ut.team_id = c.team_id
-				  AND ut.user_id = cm.user_id
-			)
-		  )
 		`,
 		conversationID,
 	)
@@ -426,6 +414,65 @@ func (s *Server) publishChatMessageUpdate(ctx context.Context, message ChatMessa
 	}
 }
 
+// publishConversationUpdate sendet jedem Mitglied die aktualisierte
+// Konversation (Name/Bild/Selbstlöschen/Mitglieder), damit Seitenleiste und
+// geöffneter Chat live aktualisiert werden.
+func (s *Server) publishConversationUpdate(ctx context.Context, conversationID string) {
+	rows, err := s.db.Query(
+		ctx,
+		`
+		SELECT cm.user_id::TEXT, u.show_last_seen
+		FROM conversation_members cm
+		JOIN users u ON u.id = cm.user_id
+		WHERE cm.conversation_id = $1
+		`,
+		conversationID,
+	)
+	if err != nil {
+		return
+	}
+	defer rows.Close()
+
+	type member struct {
+		id           string
+		showLastSeen bool
+	}
+	members := []member{}
+	for rows.Next() {
+		var m member
+		if err := rows.Scan(&m.id, &m.showLastSeen); err != nil {
+			return
+		}
+		members = append(members, m)
+	}
+	rows.Close()
+
+	for _, m := range members {
+		conversation, err := s.getChatConversation(ctx, conversationID, m.id, m.showLastSeen)
+		if err != nil {
+			continue
+		}
+		chatSockets.publish(m.id, chatSocketEvent{
+			Type:         "conversation.updated",
+			Conversation: &conversation,
+		})
+	}
+}
+
+func (s *Server) publishChatMessagesReload(ctx context.Context, conversationID string) {
+	memberIDs, err := s.chatConversationMemberIDs(ctx, conversationID)
+	if err != nil {
+		return
+	}
+
+	for _, memberID := range memberIDs {
+		chatSockets.publish(memberID, chatSocketEvent{
+			Type:           "messages.reload",
+			ConversationID: conversationID,
+		})
+	}
+}
+
 func chatUserDisplayName(user ChatUser) string {
 	if user.DisplayName != "" {
 		return user.DisplayName
@@ -439,31 +486,32 @@ func chatUserDisplayName(user ChatUser) string {
 func (s *Server) chatNotificationTitle(
 	ctx context.Context,
 	message ChatMessage,
-) (string, string, error) {
+) (string, string, string, error) {
 	var conversationType string
 	var conversationName string
+	var conversationImage string
 
 	err := s.db.QueryRow(
 		ctx,
 		`
-		SELECT type, name
+		SELECT type, name, channel_image
 		FROM conversations
 		WHERE id = $1
 		`,
 		message.ConversationID,
-	).Scan(&conversationType, &conversationName)
+	).Scan(&conversationType, &conversationName, &conversationImage)
 	if err != nil {
-		return "", "", err
+		return "", "", "", err
 	}
 
 	senderName := chatUserDisplayName(message.Sender)
 
-	if conversationType == "team" && conversationName != "" {
+	if conversationType == "group" && conversationName != "" {
-		return senderName + " in " + conversationName, conversationType, nil
+		return senderName + " in " + conversationName, conversationType, conversationImage, nil
 	}
 	if conversationType == "channel" && conversationName != "" {
-		return "Neue Meldung in " + conversationName, conversationType, nil
+		return "Neue Meldung in " + conversationName, conversationType, conversationImage, nil
 	}
 
-	return "Neue Nachricht von " + senderName, conversationType, nil
+	return "Neue Nachricht von " + senderName, conversationType, conversationImage, nil
 }

backend/cmd/vapid/main.go

@@ -0,0 +1,96 @@
+package main
+
+import (
+	"flag"
+	"fmt"
+	"log"
+	"os"
+	"strings"
+
+	webpush "github.com/SherClockHolmes/webpush-go"
+	"github.com/joho/godotenv"
+)
+
+func main() {
+	writeEnv := flag.Bool("write-env", false, "VAPID-Schlüssel direkt in eine .env-Datei schreiben")
+	envPath := flag.String("env", ".env", "Pfad der zu aktualisierenden .env-Datei")
+	flag.Parse()
+
+	_ = godotenv.Load()
+
+	privateKey, publicKey, err := webpush.GenerateVAPIDKeys()
+	if err != nil {
+		log.Fatal(err)
+	}
+
+	email := strings.TrimSpace(os.Getenv("ADMIN_EMAIL"))
+	if email == "" {
+		email = "admin@example.com"
+	}
+
+	values := map[string]string{
+		"VAPID_PUBLIC_KEY":  publicKey,
+		"VAPID_PRIVATE_KEY": privateKey,
+		"VAPID_SUBSCRIBER":  "mailto:" + email,
+	}
+
+	if *writeEnv {
+		if err := writeVAPIDEnv(*envPath, values); err != nil {
+			log.Fatal(err)
+		}
+		fmt.Printf("VAPID-Konfiguration wurde in %s geschrieben.\n", *envPath)
+		return
+	}
+
+	fmt.Printf("VAPID_PUBLIC_KEY=%s\n", values["VAPID_PUBLIC_KEY"])
+	fmt.Printf("VAPID_PRIVATE_KEY=%s\n", values["VAPID_PRIVATE_KEY"])
+	fmt.Printf("VAPID_SUBSCRIBER=%s\n", values["VAPID_SUBSCRIBER"])
+}
+
+func writeVAPIDEnv(path string, values map[string]string) error {
+	content, err := os.ReadFile(path)
+	if err != nil && !os.IsNotExist(err) {
+		return err
+	}
+
+	lines := []string{}
+	if len(content) > 0 {
+		lines = strings.Split(strings.ReplaceAll(string(content), "\r\n", "\n"), "\n")
+	}
+
+	for _, line := range lines {
+		key, value, found := strings.Cut(line, "=")
+		if !found {
+			continue
+		}
+		if (key == "VAPID_PUBLIC_KEY" || key == "VAPID_PRIVATE_KEY") &&
+			strings.TrimSpace(value) != "" {
+			return fmt.Errorf("in %s sind bereits VAPID-Schlüssel vorhanden", path)
+		}
+	}
+
+	updated := map[string]bool{}
+	for index, line := range lines {
+		key, _, found := strings.Cut(line, "=")
+		if !found {
+			continue
+		}
+		if value, ok := values[key]; ok {
+			lines[index] = key + "=" + value
+			updated[key] = true
+		}
+	}
+
+	for _, key := range []string{
+		"VAPID_PUBLIC_KEY",
+		"VAPID_PRIVATE_KEY",
+		"VAPID_SUBSCRIBER",
+	} {
+		if !updated[key] {
+			lines = append(lines, key+"="+values[key])
+		}
+	}
+
+	output := strings.TrimRight(strings.Join(lines, "\n"), "\n") + "\n"
+	return os.WriteFile(path, []byte(output), 0o600)
+}

backend/go.mod

@@ -5,6 +5,7 @@ module main
 go 1.26.2
 
 require (
+	github.com/SherClockHolmes/webpush-go v1.4.0
 	github.com/coder/websocket v1.8.14
 	github.com/golang-jwt/jwt/v5 v5.3.1
 	github.com/jackc/pgx/v5 v5.9.2

backend/go.sum

@@ -1,10 +1,14 @@
+github.com/SherClockHolmes/webpush-go v1.4.0 h1:ocnzNKWN23T9nvHi6IfyrQjkIc0oJWv1B1pULsf9i3s=
+github.com/SherClockHolmes/webpush-go v1.4.0/go.mod h1:XSq8pKX11vNV8MJEMwjrlTkxhAj1zKfxmyhdV7Pd6UA=
 github.com/coder/websocket v1.8.14 h1:9L0p0iKiNOibykf283eHkKUHHrpG7f65OE3BhhO7v9g=
 github.com/coder/websocket v1.8.14/go.mod h1:NX3SzP+inril6yawo5CQXx8+fk145lPDC6pumgx0mVg=
 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 v5.2.1/go.mod h1:pqrtFR0X4osieyHYxtmOUWsAWrfe1Q5UVIyoH402zdk=
 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/google/go-cmp v0.6.0/go.mod h1:17dUlkBOakJ0+DkrSSNjCkIjxS6bF9zb3elmeNGIjoY=
 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/pgservicefile v0.0.0-20240606120523-5a60cdf6a761 h1:iCEnooe7UlwOQYpKFhBabPMi4aNAfoODPEFNiAnClxo=
@@ -22,12 +26,75 @@ github.com/stretchr/testify v1.3.0/go.mod h1:M5WIy9Dh21IEIfnGCwXGc5bZfKNJtfHm1UV
 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=
+github.com/yuin/goldmark v1.4.13/go.mod h1:6yULJ656Px+3vBD8DxQVa3kxgyrAnzto9xy5taEt/CY=
+golang.org/x/crypto v0.0.0-20190308221718-c2843e01d9a2/go.mod h1:djNgcEr1/C05ACkg1iLfiJU5Ep61QUkGW8qpdssI0+w=
+golang.org/x/crypto v0.0.0-20210921155107-089bfa567519/go.mod h1:GvvjBRRGRdwPK5ydBHafDWAxML/pGHZbMvKqRZ5+Abc=
+golang.org/x/crypto v0.13.0/go.mod h1:y6Z2r+Rw4iayiXXAIxJIDAJ1zMW4yaTpebo8fPOliYc=
+golang.org/x/crypto v0.19.0/go.mod h1:Iy9bg/ha4yyC70EfRS8jz+B6ybOBKMaSxLj6P6oBDfU=
+golang.org/x/crypto v0.23.0/go.mod h1:CKFgDieR+mRhux2Lsu27y0fO304Db0wZe70UKqHu0v8=
+golang.org/x/crypto v0.31.0/go.mod h1:kDsLvtWBEx7MV9tJOj9bnXsPbxwJQ6csT/x4KIN4Ssk=
 golang.org/x/crypto v0.51.0 h1:IBPXwPfKxY7cWQZ38ZCIRPI50YLeevDLlLnyC5wRGTI=
 golang.org/x/crypto v0.51.0/go.mod h1:8AdwkbraGNABw2kOX6YFPs3WM22XqI4EXEd8g+x7Oc8=
+golang.org/x/mod v0.6.0-dev.0.20220419223038-86c51ed26bb4/go.mod h1:jJ57K6gSWd91VN4djpZkiMVwK6gcyfeH4XE8wZrZaV4=
+golang.org/x/mod v0.8.0/go.mod h1:iBbtSCu2XBx23ZKBPSOrRkjjQPZFPuis4dIYUhu/chs=
+golang.org/x/mod v0.12.0/go.mod h1:iBbtSCu2XBx23ZKBPSOrRkjjQPZFPuis4dIYUhu/chs=
+golang.org/x/mod v0.15.0/go.mod h1:hTbmBsO62+eylJbnUtE2MGJUyE7QWk4xUqPFrRgJ+7c=
+golang.org/x/mod v0.17.0/go.mod h1:hTbmBsO62+eylJbnUtE2MGJUyE7QWk4xUqPFrRgJ+7c=
+golang.org/x/net v0.0.0-20190620200207-3b0461eec859/go.mod h1:z5CRVTTTmAJ677TzLLGU+0bjPO0LkuOLi4/5GtJWs/s=
+golang.org/x/net v0.0.0-20210226172049-e18ecbb05110/go.mod h1:m0MpNAwzfU5UDzcl9v0D8zg8gWTRqZa9RBIspLL5mdg=
+golang.org/x/net v0.0.0-20220722155237-a158d28d115b/go.mod h1:XRhObCWvk6IyKnWLug+ECip1KBveYUHfp+8e9klMJ9c=
+golang.org/x/net v0.6.0/go.mod h1:2Tu9+aMcznHK/AK1HMvgo6xiTLG5rD5rZLDS+rp2Bjs=
+golang.org/x/net v0.10.0/go.mod h1:0qNGK6F8kojg2nk9dLZ2mShWaEBan6FAoqfSigmmuDg=
+golang.org/x/net v0.15.0/go.mod h1:idbUs1IY1+zTqbi8yxTbhexhEEk5ur9LInksu6HrEpk=
+golang.org/x/net v0.21.0/go.mod h1:bIjVDfnllIU7BJ2DNgfnXvpSvtn8VRwhlsaeUTyUS44=
+golang.org/x/net v0.25.0/go.mod h1:JkAGAh7GEvH74S6FOH42FLoXpXbE/aqXSrIQjXgsiwM=
+golang.org/x/sync v0.0.0-20190423024810-112230192c58/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=
+golang.org/x/sync v0.0.0-20220722155255-886fb9371eb4/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=
+golang.org/x/sync v0.1.0/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=
+golang.org/x/sync v0.3.0/go.mod h1:FU7BRWz2tNW+3quACPkgCx/L+uEAv1htQ0V83Z9Rj+Y=
+golang.org/x/sync v0.6.0/go.mod h1:Czt+wKu1gCyEFDUtn0jG5QVvpJ6rzVqr5aXyt9drQfk=
+golang.org/x/sync v0.7.0/go.mod h1:Czt+wKu1gCyEFDUtn0jG5QVvpJ6rzVqr5aXyt9drQfk=
+golang.org/x/sync v0.10.0/go.mod h1:Czt+wKu1gCyEFDUtn0jG5QVvpJ6rzVqr5aXyt9drQfk=
 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/sys v0.0.0-20190215142949-d0b11bdaac8a/go.mod h1:STP8DvDyc/dI5b8T5hshtkjS+E42TnysNCUPdjciGhY=
+golang.org/x/sys v0.0.0-20201119102817-f84b799fce68/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
+golang.org/x/sys v0.0.0-20210615035016-665e8c7367d1/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
+golang.org/x/sys v0.0.0-20220520151302-bc2c85ada10a/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
+golang.org/x/sys v0.0.0-20220722155257-8c9f86f7a55f/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
+golang.org/x/sys v0.5.0/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
+golang.org/x/sys v0.8.0/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
+golang.org/x/sys v0.12.0/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
+golang.org/x/sys v0.17.0/go.mod h1:/VUhepiaJMQUp4+oa/7Zr1D23ma6VTLIYjOOTFZPUcA=
+golang.org/x/sys v0.20.0/go.mod h1:/VUhepiaJMQUp4+oa/7Zr1D23ma6VTLIYjOOTFZPUcA=
+golang.org/x/sys v0.28.0/go.mod h1:/VUhepiaJMQUp4+oa/7Zr1D23ma6VTLIYjOOTFZPUcA=
+golang.org/x/telemetry v0.0.0-20240228155512-f48c80bd79b2/go.mod h1:TeRTkGYfJXctD9OcfyVLyj2J3IxLnKwHJR8f4D8a3YE=
+golang.org/x/term v0.0.0-20201126162022-7de9c90e9dd1/go.mod h1:bj7SfCRtBDWHUb9snDiAeCFNEtKQo2Wmx5Cou7ajbmo=
+golang.org/x/term v0.0.0-20210927222741-03fcf44c2211/go.mod h1:jbD1KX2456YbFQfuXm/mYQcufACuNUgVhRMnK/tPxf8=
+golang.org/x/term v0.5.0/go.mod h1:jMB1sMXY+tzblOD4FWmEbocvup2/aLOaQEp7JmGp78k=
+golang.org/x/term v0.8.0/go.mod h1:xPskH00ivmX89bAKVGSKKtLOWNx2+17Eiy94tnKShWo=
+golang.org/x/term v0.12.0/go.mod h1:owVbMEjm3cBLCHdkQu9b1opXd4ETQWc3BhuQGKgXgvU=
+golang.org/x/term v0.17.0/go.mod h1:lLRBjIVuehSbZlaOtGMbcMncT+aqLLLmKrsjNrUguwk=
+golang.org/x/term v0.20.0/go.mod h1:8UkIAJTvZgivsXaD6/pH6U9ecQzZ45awqEOzuCvwpFY=
+golang.org/x/term v0.27.0/go.mod h1:iMsnZpn0cago0GOrHO2+Y7u7JPn5AylBrcoWkElMTSM=
+golang.org/x/text v0.3.0/go.mod h1:NqM8EUOU14njkJ3fqMW+pc6Ldnwhi/IjpwHt7yyuwOQ=
+golang.org/x/text v0.3.3/go.mod h1:5Zoc/QRtKVWzQhOtBMvqHzDpF6irO9z98xDceosuGiQ=
+golang.org/x/text v0.3.7/go.mod h1:u+2+/6zg+i71rQMx5EYifcz6MCKuco9NR6JIITiCfzQ=
+golang.org/x/text v0.7.0/go.mod h1:mrYo+phRRbMaCq/xk9113O4dZlRixOauAjOtrjsXDZ8=
+golang.org/x/text v0.9.0/go.mod h1:e1OnstbJyHTd6l/uOt8jFFHp6TRDWZR/bV3emEE/zU8=
+golang.org/x/text v0.13.0/go.mod h1:TvPlkZtksWOMsz7fbANvkp4WM8x/WCo/om8BMLbz+aE=
+golang.org/x/text v0.14.0/go.mod h1:18ZOQIKpY8NJVqYksKHtTdi31H5itFRjB5/qKTNYzSU=
+golang.org/x/text v0.15.0/go.mod h1:18ZOQIKpY8NJVqYksKHtTdi31H5itFRjB5/qKTNYzSU=
+golang.org/x/text v0.21.0/go.mod h1:4IBbMaMmOPCJ8SecivzSH54+73PCFmPWxNTLm+vZkEQ=
 golang.org/x/text v0.37.0 h1:Cqjiwd9eSg8e0QAkyCaQTNHFIIzWtidPahFWR83rTrc=
 golang.org/x/text v0.37.0/go.mod h1:a5sjxXGs9hsn/AJVwuElvCAo9v8QYLzvavO5z2PiM38=
+golang.org/x/tools v0.0.0-20180917221912-90fa682c2a6e/go.mod h1:n7NCudcB/nEzxVGmLbDWY5pfWTLqBcC2KZ6jyYvM4mQ=
+golang.org/x/tools v0.0.0-20191119224855-298f0cb1881e/go.mod h1:b+2E5dAYhXwXZwtnZ6UAqBI28+e2cm9otk0dWdXHAEo=
+golang.org/x/tools v0.1.12/go.mod h1:hNGJHUnrk76NpqgfD5Aqm5Crs+Hm0VOH/i9J2+nxYbc=
+golang.org/x/tools v0.6.0/go.mod h1:Xwgl3UAJ/d3gWutnCtw505GrjyAbvKui8lOU390QaIU=
+golang.org/x/tools v0.13.0/go.mod h1:HvlwmtVNQAhOuCjW7xxvovg8wbNq7LwfXh/k7wXUl58=
+golang.org/x/tools v0.21.1-0.20240508182429-e35e4ccd0d2d/go.mod h1:aiJjzUbINMkxbQROHiO6hDPo2LHcIPhhQsa9DLh0yGk=
+golang.org/x/xerrors v0.0.0-20190717185122-a985d3407aa7/go.mod h1:I/5z698sn9Ka8TeJc9MKroUUfqBBauWjQqLJ2OPfmY0=
 gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
 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=

backend/main.go

@@ -38,6 +38,10 @@ func main() {
 
 	server := NewServer(db, jwtSecret, frontendOrigin)
 	server.startPresenceMonitor(ctx)
+	server.startDisappearingMessagesMonitor(ctx)
+	if !server.webPushConfigured() {
+		log.Println("Web Push ist nicht konfiguriert. VAPID_PUBLIC_KEY und VAPID_PRIVATE_KEY sowie eine Absenderadresse fehlen.")
+	}
 
 	log.Printf("Backend läuft auf http://localhost:%s", port)
 

backend/notification_preferences.go

@@ -12,34 +12,48 @@ import (
 )
 
 type notificationPreferencesResponse struct {
-	InAppEnabled      bool   `json:"inAppEnabled"`
+	SoundEnabled        bool   `json:"soundEnabled"`
-	SoundEnabled      bool   `json:"soundEnabled"`
+	SoundName           string `json:"soundName"`
-	SoundName         string `json:"soundName"`
+	EmailEnabled        bool   `json:"emailEnabled"`
-	EmailEnabled      bool   `json:"emailEnabled"`
+	DeviceUpdates       bool   `json:"deviceUpdates"`
-	OperationUpdates  bool   `json:"operationUpdates"`
+	DeviceJournals      bool   `json:"deviceJournals"`
-	OperationJournals bool   `json:"operationJournals"`
+	ChatMessages        bool   `json:"chatMessages"`
-	DeviceUpdates     bool   `json:"deviceUpdates"`
+	ChannelMessages     bool   `json:"channelMessages"`
-	DeviceJournals    bool   `json:"deviceJournals"`
+	DesktopEnabled      bool   `json:"desktopEnabled"`
-	SystemMessages    bool   `json:"systemMessages"`
+	PushChatMessages    bool   `json:"pushChatMessages"`
-	ChatMessages      bool   `json:"chatMessages"`
+	PushChannelMessages bool   `json:"pushChannelMessages"`
-	ChannelMessages   bool   `json:"channelMessages"`
-	DesktopEnabled    bool   `json:"desktopEnabled"`
 }
 
 func defaultNotificationPreferences() notificationPreferencesResponse {
 	return notificationPreferencesResponse{
-		InAppEnabled:      true,
+		SoundEnabled:        false,
-		SoundEnabled:      false,
+		SoundName:           "default",
-		SoundName:         "default",
+		EmailEnabled:        false,
-		EmailEnabled:      false,
+		DeviceUpdates:       true,
-		OperationUpdates:  true,
+		DeviceJournals:      true,
-		OperationJournals: true,
+		ChatMessages:        true,
-		DeviceUpdates:     true,
+		ChannelMessages:     true,
-		DeviceJournals:    true,
+		DesktopEnabled:      false,
-		SystemMessages:    true,
+		PushChatMessages:    true,
-		ChatMessages:      true,
+		PushChannelMessages: true,
-		ChannelMessages:   true,
+	}
-		DesktopEnabled:    false,
+}
+
+// shouldPushNotification entscheidet anhand der granularen Push-Einstellungen,
+// ob für den jeweiligen Benachrichtigungstyp ein Web-Push gesendet werden soll.
+// Es deckt aktuell die Nachrichtentypen ab, für die der Web-Push-Payload korrekt
+// aufgebaut werden kann (Chat- und Channel-Nachrichten).
+func shouldPushNotification(
+	preferences notificationPreferencesResponse,
+	notificationType string,
+) bool {
+	switch notificationType {
+	case "channel.message":
+		return preferences.PushChannelMessages
+	case "chat.message":
+		return preferences.PushChatMessages
+	default:
+		return false
 	}
 }
 
@@ -100,49 +114,43 @@ func (s *Server) handleUpdateNotificationPreferences(w http.ResponseWriter, r *h
 		`
 		INSERT INTO notification_preferences (
 			user_id,
-			in_app_enabled,
 			sound_enabled,
 			sound_name,
 			email_enabled,
-			operation_updates,
-			operation_journals,
 			device_updates,
 			device_journals,
-			system_messages,
 			chat_messages,
 			channel_messages,
-			desktop_enabled
+			desktop_enabled,
+			push_chat_messages,
+			push_channel_messages
 		)
-		VALUES ($1, $2, $3, $4, $5, $6, $7, $8, $9, $10, $11, $12, $13)
+		VALUES ($1, $2, $3, $4, $5, $6, $7, $8, $9, $10, $11)
 		ON CONFLICT (user_id)
 		DO UPDATE SET
-			in_app_enabled = EXCLUDED.in_app_enabled,
 			sound_enabled = EXCLUDED.sound_enabled,
 			sound_name = EXCLUDED.sound_name,
 			email_enabled = EXCLUDED.email_enabled,
-			operation_updates = EXCLUDED.operation_updates,
-			operation_journals = EXCLUDED.operation_journals,
 			device_updates = EXCLUDED.device_updates,
 			device_journals = EXCLUDED.device_journals,
-			system_messages = EXCLUDED.system_messages,
 			chat_messages = EXCLUDED.chat_messages,
 			channel_messages = EXCLUDED.channel_messages,
 			desktop_enabled = EXCLUDED.desktop_enabled,
+			push_chat_messages = EXCLUDED.push_chat_messages,
+			push_channel_messages = EXCLUDED.push_channel_messages,
 			updated_at = now()
 		`,
 		user.ID,
-		input.InAppEnabled,
 		input.SoundEnabled,
 		input.SoundName,
 		input.EmailEnabled,
-		input.OperationUpdates,
-		input.OperationJournals,
 		input.DeviceUpdates,
 		input.DeviceJournals,
-		input.SystemMessages,
 		input.ChatMessages,
 		input.ChannelMessages,
 		input.DesktopEnabled,
+		input.PushChatMessages,
+		input.PushChannelMessages,
 	)
 	if err != nil {
 		writeError(w, http.StatusInternalServerError, "Benachrichtigungseinstellungen konnten nicht gespeichert werden")
@@ -167,36 +175,32 @@ func (s *Server) getNotificationPreferences(ctx context.Context, userID string)
 		ctx,
 		`
 		SELECT
-			in_app_enabled,
 			sound_enabled,
 			COALESCE(sound_name, 'default'),
 			email_enabled,
-			operation_updates,
-			operation_journals,
 			device_updates,
 			device_journals,
-			system_messages,
 			chat_messages,
 			channel_messages,
-			desktop_enabled
+			desktop_enabled,
+			push_chat_messages,
+			push_channel_messages
 		FROM notification_preferences
 		WHERE user_id = $1
 		LIMIT 1
 		`,
 		userID,
 	).Scan(
-		&settings.InAppEnabled,
 		&settings.SoundEnabled,
 		&settings.SoundName,
 		&settings.EmailEnabled,
-		&settings.OperationUpdates,
-		&settings.OperationJournals,
 		&settings.DeviceUpdates,
 		&settings.DeviceJournals,
-		&settings.SystemMessages,
 		&settings.ChatMessages,
 		&settings.ChannelMessages,
 		&settings.DesktopEnabled,
+		&settings.PushChatMessages,
+		&settings.PushChannelMessages,
 	)
 
 	settings.SoundName = normalizeNotificationSoundName(settings.SoundName)

backend/notifications.go

@@ -104,24 +104,14 @@ func shouldDeliverNotification(
 	case strings.HasPrefix(notificationType, "chat.") || entityType == "chat":
 		return preferences.ChatMessages
 
-	case !preferences.InAppEnabled:
-		return false
-
-	case notificationType == "operation.journal":
-		return preferences.OperationJournals
-
-	case strings.HasPrefix(notificationType, "operation.") || entityType == "operation":
-		return preferences.OperationUpdates
-
 	case notificationType == "device.journal":
 		return preferences.DeviceJournals
 
 	case strings.HasPrefix(notificationType, "device.") || entityType == "device":
 		return preferences.DeviceUpdates
 
-	case strings.HasPrefix(notificationType, "system.") || entityType == "system":
+	// Systemmeldungen werden immer ausgeliefert; Einsatz-Benachrichtigungen
-		return preferences.SystemMessages
+	// werden ausschließlich als stille Events gesendet (siehe createAndPublish).
-
 	default:
 		return true
 	}
@@ -157,7 +147,7 @@ func (s *Server) createAndPublishNotification(
 		return nil
 	}
 
-	inAppVisible := silent || (preferences.InAppEnabled && entityType != "chat")
+	inAppVisible := silent || entityType != "chat"
 
 	var notification Notification
 	var rawData []byte
@@ -229,7 +219,7 @@ func (s *Server) createAndPublishNotification(
 	if !notification.Silent {
 		notification.SoundName = notificationSoundName(preferences)
 		notification.Desktop = preferences.DesktopEnabled
-		notification.InApp = preferences.InAppEnabled
+		notification.InApp = true
 		if notification.EntityType == "chat" {
 			if notification.Type == "channel.message" {
 				notification.InApp = preferences.ChannelMessages
@@ -240,6 +230,11 @@ func (s *Server) createAndPublishNotification(
 	}
 
 	notificationsBroker.publish(notification)
+	if !notification.Silent &&
+		preferences.DesktopEnabled &&
+		shouldPushNotification(preferences, notification.Type) {
+		s.publishWebPushAsync(notification)
+	}
 
 	return nil
 }
@@ -478,6 +473,8 @@ func (s *Server) createOperationNotification(
 			return err
 		}
 
+		// Einsatz-Benachrichtigungen werden ausschließlich als stille Events
+		// gesendet (kein sichtbarer Toast / keine Notification-Center-Einträge).
 		if err := s.createAndPublishNotification(
 			ctx,
 			recipientID,
@@ -487,7 +484,7 @@ func (s *Server) createOperationNotification(
 			"operation",
 			operation.ID,
 			dataJSON,
-			false,
+			true,
 		); err != nil {
 			return err
 		}

backend/push_notifications.go

@@ -0,0 +1,508 @@
+package main
+
+import (
+	"context"
+	"crypto/hmac"
+	"crypto/sha256"
+	"crypto/subtle"
+	"encoding/base64"
+	"encoding/hex"
+	"encoding/json"
+	"errors"
+	"fmt"
+	"hash/fnv"
+	"html"
+	"io"
+	"log"
+	"net/http"
+	"net/url"
+	"strings"
+	"time"
+
+	webpush "github.com/SherClockHolmes/webpush-go"
+)
+
+const (
+	maxPushSubscriptionBodyBytes = 16 * 1024
+	maxPushIconImageBytes        = 3 * 1024 * 1024
+)
+
+type pushSubscriptionRequest struct {
+	Endpoint   string `json:"endpoint"`
+	APIBaseURL string `json:"apiBaseUrl"`
+	Keys       struct {
+		P256dh string `json:"p256dh"`
+		Auth   string `json:"auth"`
+	} `json:"keys"`
+}
+
+type storedPushSubscription struct {
+	Endpoint   string
+	P256dh     string
+	Auth       string
+	APIBaseURL string
+}
+
+type webPushPayload struct {
+	Title string `json:"title"`
+	Body  string `json:"body"`
+	Icon  string `json:"icon,omitempty"`
+	Badge string `json:"badge,omitempty"`
+	Tag   string `json:"tag,omitempty"`
+	URL   string `json:"url"`
+}
+
+func (s *Server) webPushConfigured() bool {
+	return s.vapidPublicKey != "" &&
+		s.vapidPrivateKey != "" &&
+		s.vapidSubscriber != ""
+}
+
+func (s *Server) handleGetPushConfig(w http.ResponseWriter, r *http.Request) {
+	writeJSON(w, http.StatusOK, map[string]any{
+		"enabled":   s.webPushConfigured(),
+		"publicKey": s.vapidPublicKey,
+	})
+}
+
+func (s *Server) handleSavePushSubscription(w http.ResponseWriter, r *http.Request) {
+	if !s.webPushConfigured() {
+		writeError(w, http.StatusServiceUnavailable, "Web Push ist auf dem Server noch nicht konfiguriert")
+		return
+	}
+
+	user, userOK := userFromContext(r.Context())
+	sessionID, sessionOK := s.currentSessionIDFromRequest(r)
+	if !userOK || !sessionOK {
+		writeError(w, http.StatusUnauthorized, "Unauthorized")
+		return
+	}
+
+	r.Body = http.MaxBytesReader(w, r.Body, maxPushSubscriptionBodyBytes)
+	var input pushSubscriptionRequest
+	if err := readJSON(r, &input); err != nil {
+		writeError(w, http.StatusBadRequest, "Ungültiges Push-Abonnement")
+		return
+	}
+
+	input.Endpoint = strings.TrimSpace(input.Endpoint)
+	input.Keys.P256dh = strings.TrimSpace(input.Keys.P256dh)
+	input.Keys.Auth = strings.TrimSpace(input.Keys.Auth)
+	apiBaseURL, err := normalizePushAPIBaseURL(input.APIBaseURL)
+	if err != nil ||
+		input.Endpoint == "" ||
+		input.Keys.P256dh == "" ||
+		input.Keys.Auth == "" {
+		writeError(w, http.StatusBadRequest, "Ungültiges Push-Abonnement")
+		return
+	}
+
+	endpointURL, err := url.Parse(input.Endpoint)
+	if err != nil ||
+		endpointURL.Host == "" ||
+		(endpointURL.Scheme != "http" && endpointURL.Scheme != "https") {
+		writeError(w, http.StatusBadRequest, "Ungültiger Push-Endpunkt")
+		return
+	}
+
+	_, err = s.db.Exec(
+		r.Context(),
+		`
+		INSERT INTO push_subscriptions (
+			endpoint,
+			user_id,
+			session_id,
+			p256dh,
+			auth,
+			api_base_url,
+			user_agent,
+			expires_at
+		)
+		VALUES ($1, $2, $3, $4, $5, $6, $7, now() + interval '24 hours')
+		ON CONFLICT (endpoint)
+		DO UPDATE SET
+			user_id = EXCLUDED.user_id,
+			session_id = EXCLUDED.session_id,
+			p256dh = EXCLUDED.p256dh,
+			auth = EXCLUDED.auth,
+			api_base_url = EXCLUDED.api_base_url,
+			user_agent = EXCLUDED.user_agent,
+			expires_at = EXCLUDED.expires_at,
+			updated_at = now()
+		`,
+		input.Endpoint,
+		user.ID,
+		sessionID,
+		input.Keys.P256dh,
+		input.Keys.Auth,
+		apiBaseURL,
+		strings.TrimSpace(r.UserAgent()),
+	)
+	if err != nil {
+		writeError(w, http.StatusInternalServerError, "Push-Abonnement konnte nicht gespeichert werden")
+		return
+	}
+
+	writeJSON(w, http.StatusOK, map[string]bool{"subscribed": true})
+}
+
+func (s *Server) handleDeletePushSubscription(w http.ResponseWriter, r *http.Request) {
+	user, ok := userFromContext(r.Context())
+	if !ok {
+		writeError(w, http.StatusUnauthorized, "Unauthorized")
+		return
+	}
+
+	r.Body = http.MaxBytesReader(w, r.Body, maxPushSubscriptionBodyBytes)
+	var input struct {
+		Endpoint string `json:"endpoint"`
+	}
+	if err := readJSON(r, &input); err != nil {
+		writeError(w, http.StatusBadRequest, "Ungültiges Push-Abonnement")
+		return
+	}
+
+	_, err := s.db.Exec(
+		r.Context(),
+		`DELETE FROM push_subscriptions WHERE endpoint = $1 AND user_id = $2`,
+		strings.TrimSpace(input.Endpoint),
+		user.ID,
+	)
+	if err != nil {
+		writeError(w, http.StatusInternalServerError, "Push-Abonnement konnte nicht entfernt werden")
+		return
+	}
+
+	writeJSON(w, http.StatusOK, map[string]bool{"subscribed": false})
+}
+
+func normalizePushAPIBaseURL(value string) (string, error) {
+	value = strings.TrimRight(strings.TrimSpace(value), "/")
+	if value == "" || len(value) > 500 {
+		return "", errors.New("ungültige API-URL")
+	}
+
+	parsed, err := url.Parse(value)
+	if err != nil ||
+		(parsed.Scheme != "http" && parsed.Scheme != "https") ||
+		parsed.Host == "" {
+		return "", errors.New("ungültige API-URL")
+	}
+
+	return value, nil
+}
+
+func (s *Server) publishWebPushAsync(notification Notification) {
+	go func() {
+		ctx, cancel := context.WithTimeout(context.Background(), 30*time.Second)
+		defer cancel()
+
+		if err := s.publishWebPush(ctx, notification); err != nil {
+			log.Printf("Web Push für User %s fehlgeschlagen: %v", notification.UserID, err)
+		}
+	}()
+}
+
+func (s *Server) publishWebPush(ctx context.Context, notification Notification) error {
+	rows, err := s.db.Query(
+		ctx,
+		`
+		SELECT
+			ps.endpoint,
+			ps.p256dh,
+			ps.auth,
+			ps.api_base_url
+		FROM push_subscriptions ps
+		JOIN user_sessions us ON us.id = ps.session_id
+		WHERE ps.user_id = $1
+		  AND us.revoked_at IS NULL
+		  AND ps.expires_at > now()
+		`,
+		notification.UserID,
+	)
+	if err != nil {
+		return err
+	}
+	defer rows.Close()
+
+	subscriptions := []storedPushSubscription{}
+	for rows.Next() {
+		var subscription storedPushSubscription
+		if err := rows.Scan(
+			&subscription.Endpoint,
+			&subscription.P256dh,
+			&subscription.Auth,
+			&subscription.APIBaseURL,
+		); err != nil {
+			return err
+		}
+		subscriptions = append(subscriptions, subscription)
+	}
+	if err := rows.Err(); err != nil {
+		return err
+	}
+
+	for _, subscription := range subscriptions {
+		payload, err := s.buildWebPushPayload(notification, subscription.APIBaseURL)
+		if err != nil {
+			continue
+		}
+
+		payloadJSON, err := json.Marshal(payload)
+		if err != nil {
+			continue
+		}
+
+		response, err := webpush.SendNotificationWithContext(
+			ctx,
+			payloadJSON,
+			&webpush.Subscription{
+				Endpoint: subscription.Endpoint,
+				Keys: webpush.Keys{
+					P256dh: subscription.P256dh,
+					Auth:   subscription.Auth,
+				},
+			},
+			&webpush.Options{
+				Subscriber:      s.vapidSubscriber,
+				VAPIDPublicKey:  s.vapidPublicKey,
+				VAPIDPrivateKey: s.vapidPrivateKey,
+				TTL:             60 * 60,
+				HTTPClient:      &http.Client{Timeout: 12 * time.Second},
+			},
+		)
+		if err != nil {
+			continue
+		}
+
+		_, _ = io.Copy(io.Discard, response.Body)
+		_ = response.Body.Close()
+
+		if response.StatusCode == http.StatusGone ||
+			response.StatusCode == http.StatusNotFound {
+			cleanupCtx, cleanupCancel := context.WithTimeout(
+				context.Background(),
+				5*time.Second,
+			)
+			_, _ = s.db.Exec(
+				cleanupCtx,
+				`DELETE FROM push_subscriptions WHERE endpoint = $1`,
+				subscription.Endpoint,
+			)
+			cleanupCancel()
+		}
+	}
+
+	return nil
+}
+
+func (s *Server) buildWebPushPayload(
+	notification Notification,
+	apiBaseURL string,
+) (webPushPayload, error) {
+	var data struct {
+		SenderID          string `json:"senderId"`
+		SenderAvatar      string `json:"senderAvatar"`
+		ConversationType  string `json:"conversationType"`
+		ConversationImage string `json:"conversationImage"`
+	}
+	if err := json.Unmarshal(notification.Data, &data); err != nil {
+		return webPushPayload{}, err
+	}
+
+	path := "/chat/" + notification.EntityID
+	if data.ConversationType == "channel" {
+		path = "/chat/channel/" + notification.EntityID
+	}
+
+	iconKind := "user"
+	iconID := data.SenderID
+	iconSource := strings.TrimSpace(data.SenderAvatar)
+	if data.ConversationType == "group" {
+		iconKind = "group"
+		iconID = notification.EntityID
+		iconSource = strings.TrimSpace(data.ConversationImage)
+	} else if data.ConversationType == "channel" || iconID == "" {
+		iconKind = "channel"
+		iconID = notification.EntityID
+		iconSource = strings.TrimSpace(data.ConversationImage)
+	}
+
+	// Externe Bild-URLs direkt verwenden. Für lokale Avatare (data:-URLs) oder
+	// fehlende Avatare auf den signierten Icon-Endpunkt verweisen, der entweder
+	// das hinterlegte Bild ausliefert oder ein Initialen-Icon erzeugt.
+	iconURL := iconSource
+	isRemote := strings.HasPrefix(iconURL, "https://") ||
+		strings.HasPrefix(iconURL, "http://")
+	if !isRemote {
+		iconURL = ""
+		if apiBaseURL != "" && iconID != "" {
+			signature := s.signPushIcon(iconKind, iconID)
+			iconURL = apiBaseURL + "/push/icons/" + iconKind + "/" + iconID + "/" + signature
+			iconURL += "?v=" + pushIconVersion(iconSource)
+		}
+	}
+
+	return webPushPayload{
+		Title: notification.Title,
+		Body:  notification.Message,
+		Icon:  iconURL,
+		Tag:   "chat-" + notification.EntityID,
+		URL:   path,
+	}, nil
+}
+
+func pushIconVersion(image string) string {
+	sum := sha256.Sum256([]byte(image))
+	return hex.EncodeToString(sum[:8])
+}
+
+func (s *Server) signPushIcon(kind string, id string) string {
+	mac := hmac.New(sha256.New, s.jwtSecret)
+	_, _ = mac.Write([]byte(kind + ":" + id))
+	return hex.EncodeToString(mac.Sum(nil))
+}
+
+func (s *Server) handlePushIcon(w http.ResponseWriter, r *http.Request) {
+	kind := strings.TrimSpace(r.PathValue("kind"))
+	id := strings.TrimSpace(r.PathValue("id"))
+	signature := strings.TrimSpace(r.PathValue("signature"))
+	expectedSignature := s.signPushIcon(kind, id)
+
+	if subtle.ConstantTimeCompare(
+		[]byte(signature),
+		[]byte(expectedSignature),
+	) != 1 {
+		http.NotFound(w, r)
+		return
+	}
+
+	var avatar string
+	var label string
+	var err error
+	switch kind {
+	case "user":
+		err = s.db.QueryRow(
+			r.Context(),
+			`SELECT COALESCE(avatar, ''), COALESCE(NULLIF(display_name, ''), username, '') FROM users WHERE id = $1`,
+			id,
+		).Scan(&avatar, &label)
+	case "channel":
+		err = s.db.QueryRow(
+			r.Context(),
+			`
+			SELECT COALESCE(channel_image, ''), COALESCE(name, '')
+			FROM conversations
+			WHERE id = $1 AND type = 'channel'
+			`,
+			id,
+		).Scan(&avatar, &label)
+	case "group":
+		err = s.db.QueryRow(
+			r.Context(),
+			`
+			SELECT COALESCE(channel_image, ''), COALESCE(name, '')
+			FROM conversations
+			WHERE id = $1 AND type = 'group'
+			`,
+			id,
+		).Scan(&avatar, &label)
+	default:
+		http.NotFound(w, r)
+		return
+	}
+
+	if err != nil {
+		http.NotFound(w, r)
+		return
+	}
+
+	if avatar != "" {
+		if contentType, image, decodeErr := decodeAvatarDataURL(avatar); decodeErr == nil {
+			w.Header().Set("Content-Type", contentType)
+			w.Header().Set("Cache-Control", "public, max-age=3600")
+			w.Header().Set("X-Content-Type-Options", "nosniff")
+			w.WriteHeader(http.StatusOK)
+			_, _ = w.Write(image)
+			return
+		}
+	}
+
+	// Kein (dekodierbares) Bild hinterlegt: deterministisches Initialen-Icon
+	// erzeugen, damit die Benachrichtigung trotzdem den Absender zeigt.
+	w.Header().Set("Content-Type", "image/svg+xml")
+	w.Header().Set("Cache-Control", "public, max-age=3600")
+	w.Header().Set("X-Content-Type-Options", "nosniff")
+	w.WriteHeader(http.StatusOK)
+	_, _ = w.Write(initialsIconSVG(label, kind+":"+id))
+}
+
+func initialsIconSVG(label string, seed string) []byte {
+	initials := deriveInitials(label)
+	hue := hueFromSeed(seed)
+	background := fmt.Sprintf("hsl(%d, 60%%, 45%%)", hue)
+
+	svg := fmt.Sprintf(
+		`<svg xmlns="http://www.w3.org/2000/svg" width="192" height="192" viewBox="0 0 192 192">`+
+			`<rect width="192" height="192" rx="40" fill="%s"/>`+
+			`<text x="96" y="96" dy="0.35em" text-anchor="middle" `+
+			`font-family="Segoe UI,Roboto,Helvetica,Arial,sans-serif" `+
+			`font-size="86" font-weight="600" fill="#ffffff">%s</text>`+
+			`</svg>`,
+		background,
+		html.EscapeString(initials),
+	)
+
+	return []byte(svg)
+}
+
+func deriveInitials(label string) string {
+	fields := strings.Fields(label)
+	if len(fields) == 0 {
+		return "?"
+	}
+
+	firstRune := func(value string) string {
+		for _, r := range value {
+			return strings.ToUpper(string(r))
+		}
+		return ""
+	}
+
+	if len(fields) == 1 {
+		runes := []rune(fields[0])
+		if len(runes) >= 2 {
+			return strings.ToUpper(string(runes[:2]))
+		}
+		return strings.ToUpper(string(runes))
+	}
+
+	return firstRune(fields[0]) + firstRune(fields[len(fields)-1])
+}
+
+func hueFromSeed(seed string) int {
+	hash := fnv.New32a()
+	_, _ = hash.Write([]byte(seed))
+	return int(hash.Sum32() % 360)
+}
+
+func decodeAvatarDataURL(value string) (string, []byte, error) {
+	metadata, encoded, found := strings.Cut(value, ",")
+	if !found || !strings.HasSuffix(metadata, ";base64") {
+		return "", nil, errors.New("ungültiges Avatarformat")
+	}
+
+	contentType := strings.TrimSuffix(strings.TrimPrefix(metadata, "data:"), ";base64")
+	switch contentType {
+	case "image/png", "image/jpeg", "image/webp", "image/gif":
+	default:
+		return "", nil, errors.New("nicht unterstütztes Avatarformat")
+	}
+
+	image, err := base64.StdEncoding.DecodeString(encoded)
+	if err != nil || len(image) == 0 || len(image) > maxPushIconImageBytes {
+		return "", nil, errors.New("ungültige Avatardaten")
+	}
+
+	return contentType, image, nil
+}

backend/routes.go

@@ -11,6 +11,7 @@ func (s *Server) Routes() http.Handler {
 
 	mux.HandleFunc("GET /health", s.handleHealth)
 	mux.HandleFunc("POST /webhooks/channels/{slug}", s.handleChannelWebhook)
+	mux.HandleFunc("GET /push/icons/{kind}/{id}/{signature}", s.handlePushIcon)
 
 	mux.HandleFunc("POST /auth/register", s.handleRegister)
 	mux.HandleFunc("POST /auth/login", s.handleLogin)
@@ -26,6 +27,9 @@ func (s *Server) Routes() http.Handler {
 
 	mux.HandleFunc("GET /settings/notifications/preferences", s.requireAuth(s.handleGetNotificationPreferences))
 	mux.HandleFunc("PUT /settings/notifications/preferences", s.requireAuth(s.handleUpdateNotificationPreferences))
+	mux.HandleFunc("GET /push/config", s.requireAuth(s.handleGetPushConfig))
+	mux.HandleFunc("POST /push/subscriptions", s.requireAuth(s.handleSavePushSubscription))
+	mux.HandleFunc("DELETE /push/subscriptions", s.requireAuth(s.handleDeletePushSubscription))
 
 	mux.HandleFunc("POST /feedback", s.requireAuth(s.handleCreateFeedback))
 
@@ -86,6 +90,7 @@ func (s *Server) Routes() http.Handler {
 	mux.HandleFunc("GET /settings/presence", s.requireAuth(s.handleGetPresenceSettings))
 	mux.HandleFunc("PUT /settings/presence", s.requireAuth(s.handleUpdatePresenceSettings))
 	mux.HandleFunc("PUT /settings/presence/status", s.requireAuth(s.handleUpdatePresenceStatus))
+	mux.HandleFunc("GET /calendar/settings", s.requireAuth(s.requireRight("calendar:read", s.handleGetCalendarSettings)))
 
 	mux.HandleFunc("GET /chat/conversations", s.requireAuth(s.handleListChatConversations))
 	mux.HandleFunc("GET /chat/search", s.requireAuth(s.handleSearchChatMessages))
@@ -100,6 +105,12 @@ func (s *Server) Routes() http.Handler {
 	mux.HandleFunc("POST /chat/conversations/{id}/messages", s.requireAuth(s.handleCreateChatMessage))
 	mux.HandleFunc("POST /chat/conversations/{id}/read", s.requireAuth(s.handleMarkChatConversationRead))
 	mux.HandleFunc("PUT /chat/conversations/{id}/mute", s.requireAuth(s.handleUpdateConversationMute))
+	mux.HandleFunc("PUT /chat/conversations/{id}/disappearing", s.requireAuth(s.handleUpdateDisappearing))
+	mux.HandleFunc("POST /chat/groups", s.requireAuth(s.handleCreateGroup))
+	mux.HandleFunc("PUT /chat/groups/{id}", s.requireAuth(s.handleUpdateGroup))
+	mux.HandleFunc("DELETE /chat/groups/{id}", s.requireAuth(s.handleDeleteGroup))
+	mux.HandleFunc("POST /chat/groups/{id}/members", s.requireAuth(s.handleAddGroupMembers))
+	mux.HandleFunc("DELETE /chat/groups/{id}/members/{userId}", s.requireAuth(s.handleRemoveGroupMember))
 
 	mux.HandleFunc("GET /dashboard/operation-changes", s.requireAuth(s.requireRight("operations:read", s.handleDashboardOperationChanges)))
 
@@ -130,6 +141,11 @@ func (s *Server) Routes() http.Handler {
 	mux.HandleFunc("POST /admin/channels", s.requireAuth(s.requireRight("administration:write", s.handleAdminCreateChannel)))
 	mux.HandleFunc("PUT /admin/channels/{id}", s.requireAuth(s.requireRight("administration:write", s.handleAdminUpdateChannel)))
 	mux.HandleFunc("POST /admin/channels/{id}/token", s.requireAuth(s.requireRight("administration:write", s.handleAdminRotateChannelToken)))
+	mux.HandleFunc("GET /admin/group-chats", s.requireAuth(s.requireRight("administration:read", s.handleAdminListGroupChats)))
+	mux.HandleFunc("PUT /admin/group-chats/{id}", s.requireAuth(s.requireRight("administration:write", s.handleAdminUpdateGroupChat)))
+	mux.HandleFunc("DELETE /admin/group-chats/{id}", s.requireAuth(s.requireRight("administration:write", s.handleAdminDeleteGroupChat)))
+	mux.HandleFunc("GET /admin/calendar/settings", s.requireAuth(s.requireRight("administration:read", s.handleGetCalendarSettings)))
+	mux.HandleFunc("PUT /admin/calendar/settings", s.requireAuth(s.requireRight("administration:write", s.handleUpdateCalendarSettings)))
 
 	/* milestone settings */
 

backend/server.go

@@ -7,6 +7,7 @@ import (
 	"crypto/subtle"
 	"errors"
 	"net/http"
+	"os"
 	"strings"
 	"sync"
 	"time"
@@ -25,11 +26,14 @@ const (
 )
 
 type Server struct {
-	db             *pgxpool.Pool
+	db              *pgxpool.Pool
-	jwtSecret      []byte
+	jwtSecret       []byte
-	frontendOrigin string
+	frontendOrigin  string
-	presenceMu     sync.Mutex
+	vapidPublicKey  string
-	presenceStatus map[string]string
+	vapidPrivateKey string
+	vapidSubscriber string
+	presenceMu      sync.Mutex
+	presenceStatus  map[string]string
 }
 
 type User struct {
@@ -92,11 +96,21 @@ type Claims struct {
 }
 
 func NewServer(db *pgxpool.Pool, jwtSecret string, frontendOrigin string) *Server {
+	vapidSubscriber := strings.TrimSpace(os.Getenv("VAPID_SUBSCRIBER"))
+	if vapidSubscriber == "" {
+		if adminEmail := strings.TrimSpace(os.Getenv("ADMIN_EMAIL")); adminEmail != "" {
+			vapidSubscriber = "mailto:" + adminEmail
+		}
+	}
+
 	return &Server{
-		db:             db,
+		db:              db,
-		jwtSecret:      []byte(jwtSecret),
+		jwtSecret:       []byte(jwtSecret),
-		frontendOrigin: frontendOrigin,
+		frontendOrigin:  frontendOrigin,
-		presenceStatus: map[string]string{},
+		vapidPublicKey:  strings.TrimSpace(os.Getenv("VAPID_PUBLIC_KEY")),
+		vapidPrivateKey: strings.TrimSpace(os.Getenv("VAPID_PRIVATE_KEY")),
+		vapidSubscriber: vapidSubscriber,
+		presenceStatus:  map[string]string{},
 	}
 }
 
@@ -252,6 +266,17 @@ func (s *Server) handleLogin(w http.ResponseWriter, r *http.Request) {
 	}
 
 	if err := bcrypt.CompareHashAndPassword([]byte(passwordHash), []byte(input.Password)); err != nil {
+		// Fehlgeschlagene Logins werden protokolliert. Diese Einträge bleiben
+		// erhalten, da das Protokoll nur bei erfolgreichem Login geleert wird.
+		s.logUserEvent(r.Context(), UserLogEntry{
+			User:     &user,
+			Request:  r,
+			Level:    UserLogLevelWarning,
+			Category: "auth",
+			Action:   "login",
+			Message:  "Login fehlgeschlagen: falsches Passwort",
+		})
+
 		writeError(w, http.StatusUnauthorized, "Invalid username/email or password")
 		return
 	}
@@ -273,10 +298,23 @@ func (s *Server) handleLogin(w http.ResponseWriter, r *http.Request) {
 	user.LastSeenAt = &now
 
 	if err := s.setSessionCookie(w, user, sessionID); err != nil {
+		s.logUserError(
+			r,
+			user,
+			"auth",
+			"login",
+			"Sitzungs-Cookie konnte nicht erstellt werden",
+			err,
+			nil,
+		)
 		writeError(w, http.StatusInternalServerError, "Could not create session")
 		return
 	}
 
+	// Erfolgreicher Login: Protokoll des Users vollständig leeren (inklusive des
+	// soeben erzeugten Sitzungs-Eintrags), damit es danach komplett leer ist.
+	s.deleteUserLogs(r.Context(), user.ID)
+
 	writeJSON(w, http.StatusOK, map[string]any{
 		"user": user,
 	})
@@ -284,6 +322,12 @@ func (s *Server) handleLogin(w http.ResponseWriter, r *http.Request) {
 
 func (s *Server) handleLogout(w http.ResponseWriter, r *http.Request) {
 	if sessionID, ok := s.currentSessionIDFromCookie(r); ok {
+		_, _ = s.db.Exec(
+			r.Context(),
+			`DELETE FROM push_subscriptions WHERE session_id = $1`,
+			sessionID,
+		)
+
 		_, _ = s.db.Exec(
 			r.Context(),
 			`

backend/setup/main.go

@@ -385,6 +385,28 @@ func createSchema(ctx context.Context, db *pgxpool.Pool) error {
 		)
 		`,
 
+		`
+		CREATE TABLE IF NOT EXISTS calendar_settings (
+			id SMALLINT PRIMARY KEY CHECK (id = 1),
+			core_working_hours JSONB NOT NULL DEFAULT '{
+				"monday": {"enabled": true, "start": "08:00", "end": "17:00"},
+				"tuesday": {"enabled": true, "start": "08:00", "end": "17:00"},
+				"wednesday": {"enabled": true, "start": "08:00", "end": "17:00"},
+				"thursday": {"enabled": true, "start": "08:00", "end": "17:00"},
+				"friday": {"enabled": true, "start": "08:00", "end": "17:00"},
+				"saturday": {"enabled": false, "start": "08:00", "end": "17:00"},
+				"sunday": {"enabled": false, "start": "08:00", "end": "17:00"}
+			}'::JSONB,
+			created_at TIMESTAMPTZ NOT NULL DEFAULT now(),
+			updated_at TIMESTAMPTZ NOT NULL DEFAULT now()
+		)
+		`,
+		`
+		INSERT INTO calendar_settings (id)
+		VALUES (1)
+		ON CONFLICT (id) DO NOTHING
+		`,
+
 		`
 		CREATE TABLE IF NOT EXISTS devices (
 			id UUID PRIMARY KEY DEFAULT gen_random_uuid(),
@@ -625,6 +647,8 @@ func createSchema(ctx context.Context, db *pgxpool.Pool) error {
 			chat_messages BOOLEAN NOT NULL DEFAULT true,
 			channel_messages BOOLEAN NOT NULL DEFAULT true,
 			desktop_enabled BOOLEAN NOT NULL DEFAULT false,
+			push_chat_messages BOOLEAN NOT NULL DEFAULT true,
+			push_channel_messages BOOLEAN NOT NULL DEFAULT true,
 
 			created_at TIMESTAMPTZ NOT NULL DEFAULT now(),
 			updated_at TIMESTAMPTZ NOT NULL DEFAULT now()
@@ -634,6 +658,24 @@ func createSchema(ctx context.Context, db *pgxpool.Pool) error {
 		`ALTER TABLE IF EXISTS notification_preferences ADD COLUMN IF NOT EXISTS chat_messages BOOLEAN NOT NULL DEFAULT true`,
 		`ALTER TABLE IF EXISTS notification_preferences ADD COLUMN IF NOT EXISTS channel_messages BOOLEAN NOT NULL DEFAULT true`,
 		`ALTER TABLE IF EXISTS notification_preferences ADD COLUMN IF NOT EXISTS desktop_enabled BOOLEAN NOT NULL DEFAULT false`,
+		`ALTER TABLE IF EXISTS notification_preferences ADD COLUMN IF NOT EXISTS push_chat_messages BOOLEAN NOT NULL DEFAULT true`,
+		`ALTER TABLE IF EXISTS notification_preferences ADD COLUMN IF NOT EXISTS push_channel_messages BOOLEAN NOT NULL DEFAULT true`,
+
+		`
+		CREATE TABLE IF NOT EXISTS push_subscriptions (
+			endpoint TEXT PRIMARY KEY,
+			user_id UUID NOT NULL REFERENCES users(id) ON DELETE CASCADE,
+			session_id UUID NOT NULL REFERENCES user_sessions(id) ON DELETE CASCADE,
+			p256dh TEXT NOT NULL,
+			auth TEXT NOT NULL,
+			api_base_url TEXT NOT NULL DEFAULT '',
+			user_agent TEXT NOT NULL DEFAULT '',
+			expires_at TIMESTAMPTZ NOT NULL DEFAULT now() + interval '24 hours',
+			created_at TIMESTAMPTZ NOT NULL DEFAULT now(),
+			updated_at TIMESTAMPTZ NOT NULL DEFAULT now()
+		)
+		`,
+		`ALTER TABLE IF EXISTS push_subscriptions ADD COLUMN IF NOT EXISTS expires_at TIMESTAMPTZ NOT NULL DEFAULT now() + interval '24 hours'`,
 
 		`
 		CREATE TABLE IF NOT EXISTS feedback (
@@ -707,7 +749,7 @@ func createSchema(ctx context.Context, db *pgxpool.Pool) error {
 			id UUID PRIMARY KEY DEFAULT gen_random_uuid(),
 
 			type TEXT NOT NULL DEFAULT 'direct'
-				CHECK (type IN ('team', 'direct', 'group', 'channel')),
+				CHECK (type IN ('direct', 'group', 'channel')),
 			name TEXT NOT NULL DEFAULT '',
 
 			team_id UUID REFERENCES teams(id) ON DELETE CASCADE,
@@ -727,12 +769,16 @@ func createSchema(ctx context.Context, db *pgxpool.Pool) error {
 
 			last_message_at TIMESTAMPTZ,
 
+			disappearing_seconds INTEGER NOT NULL DEFAULT 0,
+
 			created_at TIMESTAMPTZ NOT NULL DEFAULT now(),
 			updated_at TIMESTAMPTZ NOT NULL DEFAULT now()
 		)
 		`,
 		`ALTER TABLE IF EXISTS conversations DROP CONSTRAINT IF EXISTS conversations_type_check`,
-		`ALTER TABLE IF EXISTS conversations ADD CONSTRAINT conversations_type_check CHECK (type IN ('team', 'direct', 'group', 'channel'))`,
+		`ALTER TABLE IF EXISTS conversations ADD COLUMN IF NOT EXISTS disappearing_seconds INTEGER NOT NULL DEFAULT 0`,
+		`UPDATE conversations SET type = 'group', created_by = NULL WHERE type = 'team'`,
+		`ALTER TABLE IF EXISTS conversations ADD CONSTRAINT conversations_type_check CHECK (type IN ('direct', 'group', 'channel'))`,
 		`ALTER TABLE IF EXISTS conversations ADD COLUMN IF NOT EXISTS slug TEXT NOT NULL DEFAULT ''`,
 		`ALTER TABLE IF EXISTS conversations ADD COLUMN IF NOT EXISTS channel_source_name TEXT NOT NULL DEFAULT ''`,
 		`ALTER TABLE IF EXISTS conversations ADD COLUMN IF NOT EXISTS channel_image TEXT NOT NULL DEFAULT ''`,
@@ -768,6 +814,10 @@ func createSchema(ctx context.Context, db *pgxpool.Pool) error {
 			reply_to_message_id UUID REFERENCES messages(id) ON DELETE SET NULL,
 			forwarded_from_message_id UUID REFERENCES messages(id) ON DELETE SET NULL,
 
+			message_type TEXT NOT NULL DEFAULT 'user',
+			system_event JSONB,
+			expires_at TIMESTAMPTZ,
+
 			created_at TIMESTAMPTZ NOT NULL DEFAULT now(),
 			edited_at TIMESTAMPTZ,
 			deleted_at TIMESTAMPTZ
@@ -776,6 +826,9 @@ func createSchema(ctx context.Context, db *pgxpool.Pool) error {
 
 		`ALTER TABLE IF EXISTS messages ADD COLUMN IF NOT EXISTS reply_to_message_id UUID REFERENCES messages(id) ON DELETE SET NULL`,
 		`ALTER TABLE IF EXISTS messages ADD COLUMN IF NOT EXISTS forwarded_from_message_id UUID REFERENCES messages(id) ON DELETE SET NULL`,
+		`ALTER TABLE IF EXISTS messages ADD COLUMN IF NOT EXISTS message_type TEXT NOT NULL DEFAULT 'user'`,
+		`ALTER TABLE IF EXISTS messages ADD COLUMN IF NOT EXISTS system_event JSONB`,
+		`ALTER TABLE IF EXISTS messages ADD COLUMN IF NOT EXISTS expires_at TIMESTAMPTZ`,
 
 		// Standort-Nachrichten: lat/lng sind NULL, wenn die Nachricht keinen Standort enthält.
 		`ALTER TABLE IF EXISTS messages ADD COLUMN IF NOT EXISTS location_lat DOUBLE PRECISION`,
@@ -877,6 +930,8 @@ func createSchema(ctx context.Context, db *pgxpool.Pool) error {
 		`CREATE INDEX IF NOT EXISTS idx_notifications_entity ON notifications(entity_type, entity_id)`,
 
 		`CREATE INDEX IF NOT EXISTS idx_notification_preferences_user_id ON notification_preferences(user_id)`,
+		`CREATE INDEX IF NOT EXISTS idx_push_subscriptions_user_id ON push_subscriptions(user_id)`,
+		`CREATE INDEX IF NOT EXISTS idx_push_subscriptions_session_id ON push_subscriptions(session_id)`,
 
 		`CREATE INDEX IF NOT EXISTS idx_feedback_user_id ON feedback(user_id)`,
 		`CREATE INDEX IF NOT EXISTS idx_feedback_created_at ON feedback(created_at)`,
@@ -896,6 +951,38 @@ func createSchema(ctx context.Context, db *pgxpool.Pool) error {
 		`CREATE INDEX IF NOT EXISTS idx_conversations_type ON conversations(type)`,
 		`CREATE INDEX IF NOT EXISTS idx_conversations_last_message_at ON conversations(last_message_at DESC)`,
 		`
+		INSERT INTO conversations (type, name, team_id)
+		SELECT 'group', name, id
+		FROM teams
+		ON CONFLICT (team_id) WHERE team_id IS NOT NULL
+		DO UPDATE SET
+			type = 'group',
+			name = EXCLUDED.name,
+			created_by = NULL,
+			updated_at = now()
+		`,
+		`
+		DELETE FROM conversation_members cm
+		USING conversations c
+		WHERE cm.conversation_id = c.id
+		  AND c.team_id IS NOT NULL
+		  AND NOT EXISTS (
+			SELECT 1
+			FROM user_teams ut
+			WHERE ut.team_id = c.team_id
+			  AND ut.user_id = cm.user_id
+		  )
+		`,
+		`
+		INSERT INTO conversation_members (conversation_id, user_id)
+		SELECT c.id, ut.user_id
+		FROM conversations c
+		JOIN user_teams ut ON ut.team_id = c.team_id
+		WHERE c.type = 'group'
+		  AND c.team_id IS NOT NULL
+		ON CONFLICT (conversation_id, user_id) DO NOTHING
+		`,
+		`
 		INSERT INTO conversations (
 			type,
 			name,
@@ -925,6 +1012,7 @@ func createSchema(ctx context.Context, db *pgxpool.Pool) error {
 		`CREATE INDEX IF NOT EXISTS idx_messages_sender_id ON messages(sender_id)`,
 		`CREATE INDEX IF NOT EXISTS idx_messages_reply_to_message_id ON messages(reply_to_message_id)`,
 		`CREATE INDEX IF NOT EXISTS idx_messages_forwarded_from_message_id ON messages(forwarded_from_message_id)`,
+		`CREATE INDEX IF NOT EXISTS idx_messages_expires_at ON messages(expires_at) WHERE expires_at IS NOT NULL`,
 		`CREATE INDEX IF NOT EXISTS idx_message_attachments_message_id ON message_attachments(message_id)`,
 		`CREATE INDEX IF NOT EXISTS idx_message_attachments_uploader_id ON message_attachments(uploader_id)`,
 	}

backend/user_log.go

@@ -128,6 +128,27 @@ func (s *Server) logUserEvent(ctx context.Context, entry UserLogEntry) {
 	s.pruneAnonymousUserLogs(ctx)
 }
 
+// deleteUserLogs entfernt sämtliche Protokolleinträge eines Users. Wird nach
+// einem erfolgreichen Login aufgerufen, damit das Protokoll danach leer ist.
+func (s *Server) deleteUserLogs(ctx context.Context, userID string) {
+	userID = strings.TrimSpace(userID)
+
+	if userID == "" {
+		return
+	}
+
+	_, err := s.db.Exec(
+		ctx,
+		`DELETE FROM user_logs WHERE user_id = $1`,
+		userID,
+	)
+	if err != nil {
+		logError("User-Logs konnten beim Login nicht gelöscht werden", err, LogFields{
+			"userId": userID,
+		})
+	}
+}
+
 func (s *Server) pruneUserLogs(ctx context.Context, user *User) {
 	if user == nil || user.ID == "" {
 		return

backend/user_sessions.go

@@ -397,6 +397,12 @@ func (s *Server) handleRevokeUserSession(w http.ResponseWriter, r *http.Request)
 		return
 	}
 
+	_, _ = s.db.Exec(
+		r.Context(),
+		`DELETE FROM push_subscriptions WHERE session_id = $1`,
+		sessionID,
+	)
+
 	s.logRequestInfo(
 		r,
 		"session",

backend/user_settings.go

@@ -245,6 +245,17 @@ func (s *Server) handleLogoutOtherSessions(w http.ResponseWriter, r *http.Reques
 		return
 	}
 
+	_, _ = s.db.Exec(
+		r.Context(),
+		`
+		DELETE FROM push_subscriptions
+		WHERE user_id = $1
+		  AND session_id <> $2
+		`,
+		userID,
+		currentSessionID,
+	)
+
 	writeSettingsJSON(w, http.StatusOK, map[string]any{
 		"message": "Andere Sitzungen wurden abgemeldet",
 	})

frontend/.env.development

@@ -0,0 +1 @@
+VITE_API_URL="/api"

frontend/.gitignore

@@ -12,6 +12,9 @@ dist
 dist-ssr
 *.local
 
+# Local dev TLS certificates (mkcert)
+certs
+
 # Editor directories and files
 .vscode/*
 !.vscode/extensions.json

frontend/index.html

@@ -3,8 +3,11 @@
   <head>
     <meta charset="UTF-8" />
     <link rel="icon" type="image/svg+xml" href="/favicon.svg" />
+    <link rel="manifest" href="/manifest.webmanifest" />
     <meta name="viewport" content="width=device-width, initial-scale=1.0" />
-    <title>teg</title>
+    <meta name="theme-color" content="#4f46e5" />
+    <meta name="application-name" content="TEG" />
+    <title>TEG</title>
   </head>
   <body>
     <div id="root"></div>

frontend/package-lock.json

@@ -27,6 +27,7 @@
         "@types/node": "^24.12.3",
         "@types/react": "^19.2.14",
         "@types/react-dom": "^19.2.3",
+        "@vitejs/plugin-basic-ssl": "^2.3.0",
         "@vitejs/plugin-react": "^6.0.1",
         "eslint": "^10.3.0",
         "eslint-plugin-react-hooks": "^7.1.1",
@@ -2250,6 +2251,19 @@
         "node": "^12.20.0 || ^14.13.1 || >=16.0.0"
       }
     },
+    "node_modules/@vitejs/plugin-basic-ssl": {
+      "version": "2.3.0",
+      "resolved": "https://registry.npmjs.org/@vitejs/plugin-basic-ssl/-/plugin-basic-ssl-2.3.0.tgz",
+      "integrity": "sha512-bdyo8rB3NnQbikdMpHaML9Z1OZPBu6fFOBo+OtxsBlvMJtysWskmBcnbIDhUqgC8tcxNv/a+BcV5U+2nQMm1OQ==",
+      "dev": true,
+      "license": "MIT",
+      "engines": {
+        "node": "^18.0.0 || ^20.0.0 || >=22.0.0"
+      },
+      "peerDependencies": {
+        "vite": "^6.0.0 || ^7.0.0 || ^8.0.0"
+      }
+    },
     "node_modules/@vitejs/plugin-react": {
       "version": "6.0.1",
       "resolved": "https://registry.npmjs.org/@vitejs/plugin-react/-/plugin-react-6.0.1.tgz",

frontend/package.json

@@ -29,6 +29,7 @@
     "@types/node": "^24.12.3",
     "@types/react": "^19.2.14",
     "@types/react-dom": "^19.2.3",
+    "@vitejs/plugin-basic-ssl": "^2.3.0",
     "@vitejs/plugin-react": "^6.0.1",
     "eslint": "^10.3.0",
     "eslint-plugin-react-hooks": "^7.1.1",

frontend/public/manifest.webmanifest

@@ -0,0 +1,18 @@
+{
+  "name": "TEG",
+  "short_name": "TEG",
+  "description": "TEG Einsatz-, Geräte- und Chatverwaltung",
+  "start_url": "/",
+  "scope": "/",
+  "display": "standalone",
+  "background_color": "#030712",
+  "theme_color": "#4f46e5",
+  "icons": [
+    {
+      "src": "/favicon.svg",
+      "sizes": "any",
+      "type": "image/svg+xml",
+      "purpose": "any"
+    }
+  ]
+}

frontend/public/sw.js

@@ -0,0 +1,64 @@
+const DEFAULT_ICON = '/favicon.svg'
+
+self.addEventListener('install', () => {
+  self.skipWaiting()
+})
+
+self.addEventListener('activate', (event) => {
+  event.waitUntil(self.clients.claim())
+})
+
+self.addEventListener('push', (event) => {
+  let payload = {}
+
+  try {
+    payload = event.data ? event.data.json() : {}
+  } catch {
+    payload = {
+      title: 'Neue TEG-Nachricht',
+      body: event.data ? event.data.text() : '',
+      url: '/chat',
+    }
+  }
+
+  const title = payload.title || 'Neue TEG-Nachricht'
+  const icon = payload.icon || DEFAULT_ICON
+
+  event.waitUntil(
+    self.registration.showNotification(title, {
+      body: payload.body || '',
+      icon,
+      badge: payload.badge || DEFAULT_ICON,
+      tag: payload.tag || 'teg-message',
+      renotify: true,
+      requireInteraction: true,
+      data: {
+        url: payload.url || '/chat',
+      },
+    }),
+  )
+})
+
+self.addEventListener('notificationclick', (event) => {
+  event.notification.close()
+
+  const targetURL = new URL(
+    event.notification.data?.url || '/chat',
+    self.location.origin,
+  ).href
+
+  event.waitUntil(
+    self.clients
+      .matchAll({ type: 'window', includeUncontrolled: true })
+      .then(async (windowClients) => {
+        for (const client of windowClients) {
+          if ('navigate' in client) {
+            await client.navigate(targetURL)
+          }
+          return client.focus()
+        }
+
+        return self.clients.openWindow(targetURL)
+      }),
+  )
+})

frontend/src/App.tsx

@@ -8,7 +8,7 @@ import AppLayout from './components/AppLayout'
 import DashboardPage from './pages/DashboardPage'
 import DevicesPage from './pages/devices/DevicesPage'
 import OperationsPage from './pages/operations/OperationsPage'
-import CalendarPage from './pages/CalendarPage'
+import CalendarPage from './pages/calendar/CalendarPage'
 import DocumentsPage from './pages/DocumentsPage'
 import ReportsPage from './pages/ReportsPage'
 import SettingsPage from './pages/settings/SettingsPage'
@@ -23,6 +23,8 @@ import MilestoneDevicesPage from './pages/operations/milestone-devices/Milestone
 import { hasRight } from './components/permissions'
 import ChatPage from './pages/chat/ChatPage'
 import { recordNavigation } from './utils/activityLog'
+import { syncExistingPushSubscription } from './utils/pushNotifications'
+import { notifyNewMessage } from './utils/titleNotifier'
 
 const API_URL = import.meta.env.VITE_API_URL ?? 'http://localhost:8080'
 
@@ -78,7 +80,11 @@ function resolveNotificationImage(value: unknown) {
   }
 
   try {
-    return new URL(image, API_URL).toString()
+    const apiBaseURL = new URL(
+      `${API_URL.replace(/\/$/, '')}/`,
+      window.location.origin,
+    )
+    return new URL(image.replace(/^\//, ''), apiBaseURL).toString()
   } catch {
     return new URL('/favicon.svg', window.location.origin).toString()
   }
@@ -157,6 +163,12 @@ function App() {
     recordNavigation(location.pathname)
   }, [location.pathname])
 
+  useEffect(() => {
+    if (currentUserId) {
+      void syncExistingPushSubscription().catch(() => undefined)
+    }
+  }, [currentUserId])
+
   useEffect(() => {
     if (!currentUserId) {
       setNotifications([])
@@ -180,9 +192,6 @@ function App() {
       if (notification.entityType === 'chat') {
         const data = getNotificationData(notification)
         const senderAvatar = resolveNotificationImage(data.senderAvatar)
-        const desktopIcon =
-          senderAvatar ||
-          new URL('/favicon.svg', window.location.origin).toString()
         const senderName =
           typeof data.senderName === 'string' ? data.senderName : notification.title
         const isChannel = data.conversationType === 'channel'
@@ -190,30 +199,6 @@ function App() {
           ? `/chat/channel/${notification.entityId}`
           : `/chat/${notification.entityId}`
 
-        if (
-          notification.desktop &&
-          'Notification' in window &&
-          Notification.permission === 'granted'
-        ) {
-          try {
-            const desktopNotification = new Notification(notification.title, {
-              body: notification.message,
-              icon: desktopIcon,
-              badge: desktopIcon,
-              tag: `chat-${notification.entityId}`,
-              requireInteraction: true,
-            })
-
-            desktopNotification.onclick = () => {
-              window.focus()
-              navigate(chatPath)
-              desktopNotification.close()
-            }
-          } catch {
-            // Das sichtbare Browser-Popup darunter bleibt als Fallback erhalten.
-          }
-        }
-
         if (
           notification.inAppEnabled !== false &&
           document.visibilityState === 'visible'
@@ -252,6 +237,10 @@ function App() {
           })
         }
 
+        if (document.visibilityState !== 'visible') {
+          notifyNewMessage()
+        }
+
         playNotificationSound(notification.soundName)
         return
       }

frontend/src/components/Modal.tsx

@@ -28,6 +28,7 @@ type ModalProps = {
 
   children?: ReactNode
   panelClassName?: string
+  backdropClassName?: string
   zIndexClassName?: string
 }
 
@@ -35,6 +36,25 @@ function classNames(...classes: Array<string | false | null | undefined>) {
   return classes.filter(Boolean).join(' ')
 }
 
+export function ModalTitle({
+  children,
+  className,
+}: {
+  children: ReactNode
+  className?: string
+}) {
+  return (
+    <DialogTitle
+      className={classNames(
+        'text-base font-semibold text-gray-950 dark:text-white',
+        className,
+      )}
+    >
+      {children}
+    </DialogTitle>
+  )
+}
+
 export default function Modal({
   open,
   setOpen,
@@ -46,6 +66,7 @@ export default function Modal({
   onConfirm,
   children,
   panelClassName,
+  backdropClassName,
   zIndexClassName = 'z-[9999]',
 }: ModalProps) {
   const isSuccess = variant === 'success-single' || variant === 'success-wide'
@@ -82,7 +103,10 @@ export default function Modal({
       >
         <DialogBackdrop
           transition
-          className="fixed inset-0 z-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"
+          className={classNames(
+            'fixed inset-0 z-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',
+            backdropClassName,
+          )}
         />
 
         <div className="fixed inset-0 z-10 w-screen overflow-hidden">

frontend/src/components/calendar/calendarSettings.ts

@@ -0,0 +1,85 @@
+export const calendarWeekdays = [
+  { key: 'monday', label: 'Montag', jsDay: 1 },
+  { key: 'tuesday', label: 'Dienstag', jsDay: 2 },
+  { key: 'wednesday', label: 'Mittwoch', jsDay: 3 },
+  { key: 'thursday', label: 'Donnerstag', jsDay: 4 },
+  { key: 'friday', label: 'Freitag', jsDay: 5 },
+  { key: 'saturday', label: 'Samstag', jsDay: 6 },
+  { key: 'sunday', label: 'Sonntag', jsDay: 0 },
+] as const
+
+export type CalendarWeekdayKey = (typeof calendarWeekdays)[number]['key']
+
+export type CalendarWorkingHoursDay = {
+  enabled: boolean
+  start: string
+  end: string
+}
+
+export type CalendarCoreWorkingHours = Record<
+  CalendarWeekdayKey,
+  CalendarWorkingHoursDay
+>
+
+export type CalendarSettings = {
+  coreWorkingHours: CalendarCoreWorkingHours
+  updatedAt?: string
+}
+
+const workingDay: CalendarWorkingHoursDay = {
+  enabled: true,
+  start: '08:00',
+  end: '17:00',
+}
+
+const dayOff: CalendarWorkingHoursDay = {
+  enabled: false,
+  start: '08:00',
+  end: '17:00',
+}
+
+export function createDefaultCalendarSettings(): CalendarSettings {
+  return {
+    coreWorkingHours: {
+      monday: { ...workingDay },
+      tuesday: { ...workingDay },
+      wednesday: { ...workingDay },
+      thursday: { ...workingDay },
+      friday: { ...workingDay },
+      saturday: { ...dayOff },
+      sunday: { ...dayOff },
+    },
+  }
+}
+
+export function normalizeCalendarSettings(
+  value: Partial<CalendarSettings> | null | undefined,
+): CalendarSettings {
+  const defaults = createDefaultCalendarSettings()
+
+  return {
+    coreWorkingHours: Object.fromEntries(
+      calendarWeekdays.map(({ key }) => [
+        key,
+        {
+          ...defaults.coreWorkingHours[key],
+          ...value?.coreWorkingHours?.[key],
+        },
+      ]),
+    ) as CalendarCoreWorkingHours,
+    updatedAt: value?.updatedAt,
+  }
+}
+
+export function timeToMinutes(value: string) {
+  const [hours, minutes] = value.split(':').map(Number)
+  return hours * 60 + minutes
+}
+
+export function workingHoursForDate(
+  workingHours: CalendarCoreWorkingHours,
+  date: Date,
+) {
+  const weekday = calendarWeekdays.find(({ jsDay }) => jsDay === date.getDay())
+  return weekday ? workingHours[weekday.key] : undefined
+}

frontend/src/components/calendar/dateUtils.ts

@@ -0,0 +1,6 @@
+export function toDateKey(date: Date) {
+  const year = date.getFullYear()
+  const month = String(date.getMonth() + 1).padStart(2, '0')
+  const day = String(date.getDate()).padStart(2, '0')
+  return `${year}-${month}-${day}`
+}

frontend/src/main.tsx

@@ -7,8 +7,12 @@ import './index.css'
 import App from './App.tsx'
 import { NotificationProvider } from './components/Notifications.tsx'
 import { initActivityLog } from './utils/activityLog.ts'
+import { registerServiceWorker } from './utils/pushNotifications.ts'
 
 initActivityLog()
+void registerServiceWorker().catch(() => {
+  // Die App bleibt ohne Service Worker nutzbar, nur Hintergrund-Push entfällt.
+})
 
 createRoot(document.getElementById('root')!).render(
   <StrictMode>

frontend/src/pages/CalendarPage.tsx

@@ -1,11 +0,0 @@
-// 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/LoginPage.tsx

@@ -7,6 +7,7 @@ import Card from '../components/Card'
 import Checkbox from '../components/Checkbox'
 import type { User } from '../components/types'
 import { getCurrentSessionInfo } from '../utils/sessionInfo'
+import { clearActivityLog } from '../utils/activityLog'
 
 const API_URL = import.meta.env.VITE_API_URL ?? 'http://localhost:8080'
 
@@ -90,6 +91,10 @@ export default function LoginPage({
       const data = await response.json().catch(() => null)
       const user = data?.user as User | undefined
 
+      // Erfolgreicher Login: clientseitiges Aktivitätsprotokoll leeren, damit es
+      // (wie das serverseitige User-Protokoll) nach dem Login leer startet.
+      clearActivityLog()
+
       if (user) {
         onLogin?.(user)
       }

frontend/src/pages/administration/AdministrationPage.tsx

@@ -2,18 +2,18 @@
 
 import { useLocation, Navigate } from 'react-router'
 import {
+  CalendarDaysIcon,
   ChatBubbleLeftRightIcon,
-  HashtagIcon,
   UserGroupIcon,
   UsersIcon,
   VideoCameraIcon,
 } from '@heroicons/react/20/solid'
 import Tabs from '../../components/Tabs'
 import UsersAdministration from './users/UsersAdministration'
-import TeamsAdministration from './teams/TeamsAdministration'
 import FeedbackAdministration from './feedback/FeedbackAdministration'
 import Milestone from './milestone/Milestone'
-import ChannelsAdministration from './channels/ChannelsAdministration'
+import ChatsAdministration from './chats/ChatsAdministration'
+import CalendarAdministration from './calendar/CalendarAdministration'
 
 export default function AdministrationPage() {
   const location = useLocation()
@@ -30,16 +30,10 @@ export default function AdministrationPage() {
       current: section === 'benutzer',
     },
     {
-      name: 'Teams',
+      name: 'Teams & Chats',
-      href: '/administration/teams',
+      href: '/administration/chats/teams',
       icon: UserGroupIcon,
-      current: section === 'teams',
+      current: section === 'chats',
-    },
-    {
-      name: 'Channels',
-      href: '/administration/channels',
-      icon: HashtagIcon,
-      current: section === 'channels',
     },
     {
       name: 'Milestone',
@@ -47,6 +41,12 @@ export default function AdministrationPage() {
       icon: VideoCameraIcon,
       current: section === 'milestone',
     },
+    {
+      name: 'Kalender',
+      href: '/administration/kalender',
+      icon: CalendarDaysIcon,
+      current: section === 'kalender',
+    },
     {
       name: 'Feedback',
       href: '/administration/feedback',
@@ -55,7 +55,19 @@ export default function AdministrationPage() {
     },
   ]
 
-  if (!['benutzer', 'teams', 'channels', 'milestone', 'feedback'].includes(section)) {
+  if (section === 'teams') {
+    return <Navigate to="/administration/chats/teams" replace />
+  }
+
+  if (section === 'channels') {
+    return <Navigate to="/administration/chats/channels" replace />
+  }
+
+  if (
+    !['benutzer', 'chats', 'milestone', 'kalender', 'feedback'].includes(
+      section,
+    )
+  ) {
     return <Navigate to="/administration/benutzer" replace />
   }
 
@@ -80,14 +92,14 @@ export default function AdministrationPage() {
             </h1>
 
             <p className="mt-2 text-sm text-gray-500 dark:text-gray-400">
-              Benutzer verwalten, Teams zuweisen und Integrationen konfigurieren.
+              Benutzer, Kommunikation, Kalender und Integrationen verwalten.
             </p>
           </div>
 
           {section === 'benutzer' && <UsersAdministration />}
-          {section === 'teams' && <TeamsAdministration />}
+          {section === 'chats' && <ChatsAdministration />}
-          {section === 'channels' && <ChannelsAdministration />}
           {section === 'milestone' && <Milestone />}
+          {section === 'kalender' && <CalendarAdministration />}
           {section === 'feedback' && <FeedbackAdministration />}
         </div>
       </div>

frontend/src/pages/administration/calendar/CalendarAdministration.tsx

@@ -0,0 +1,251 @@
+import { ClockIcon } from '@heroicons/react/20/solid'
+import { useEffect, useState, type FormEvent } from 'react'
+import Button from '../../../components/Button'
+import { useNotifications } from '../../../components/Notifications'
+import Switch from '../../../components/Switch'
+import {
+  calendarWeekdays,
+  createDefaultCalendarSettings,
+  normalizeCalendarSettings,
+  timeToMinutes,
+  type CalendarSettings,
+} from '../../../components/calendar/calendarSettings'
+
+const API_URL = import.meta.env.VITE_API_URL ?? 'http://localhost:8080'
+
+const timeInputClassName =
+  'rounded-lg bg-white px-3 py-2 text-sm text-gray-900 outline-1 -outline-offset-1 outline-gray-300 focus:outline-2 focus:-outline-offset-2 focus:outline-indigo-600 disabled:cursor-not-allowed disabled:bg-gray-100 disabled:text-gray-400 dark:bg-white/5 dark:text-white dark:outline-white/10 dark:focus:outline-indigo-500 dark:disabled:bg-white/[0.03] dark:disabled:text-gray-600'
+
+export default function CalendarAdministration() {
+  const { showToast, showErrorToast } = useNotifications()
+  const [settings, setSettings] = useState<CalendarSettings>(
+    createDefaultCalendarSettings,
+  )
+  const [isLoading, setIsLoading] = useState(true)
+  const [isSaving, setIsSaving] = useState(false)
+  const [formError, setFormError] = useState('')
+
+  useEffect(() => {
+    let ignore = false
+
+    void fetch(`${API_URL}/admin/calendar/settings`, {
+      credentials: 'include',
+    })
+      .then(async (response) => {
+        const data = await response.json().catch(() => null)
+        if (!response.ok) {
+          throw new Error(
+            data?.error ?? 'Kalender-Einstellungen konnten nicht geladen werden',
+          )
+        }
+
+        if (!ignore) {
+          setSettings(normalizeCalendarSettings(data?.settings))
+        }
+      })
+      .catch((error) => {
+        if (!ignore) {
+          showErrorToast({
+            title: 'Kalender-Einstellungen konnten nicht geladen werden',
+            error,
+            fallback: 'Kalender-Einstellungen konnten nicht geladen werden',
+          })
+        }
+      })
+      .finally(() => {
+        if (!ignore) {
+          setIsLoading(false)
+        }
+      })
+
+    return () => {
+      ignore = true
+    }
+  }, [showErrorToast])
+
+  async function handleSubmit(event: FormEvent<HTMLFormElement>) {
+    event.preventDefault()
+    setFormError('')
+
+    for (const weekday of calendarWeekdays) {
+      const hours = settings.coreWorkingHours[weekday.key]
+      if (
+        hours.enabled &&
+        timeToMinutes(hours.end) <= timeToMinutes(hours.start)
+      ) {
+        setFormError(
+          `${weekday.label}: Das Ende muss nach dem Beginn liegen.`,
+        )
+        return
+      }
+    }
+
+    setIsSaving(true)
+
+    try {
+      const response = await fetch(`${API_URL}/admin/calendar/settings`, {
+        method: 'PUT',
+        credentials: 'include',
+        headers: { 'Content-Type': 'application/json' },
+        body: JSON.stringify({
+          coreWorkingHours: settings.coreWorkingHours,
+        }),
+      })
+      const data = await response.json().catch(() => null)
+
+      if (!response.ok) {
+        throw new Error(
+          data?.error ?? 'Kalender-Einstellungen konnten nicht gespeichert werden',
+        )
+      }
+
+      setSettings(normalizeCalendarSettings(data?.settings))
+      showToast({
+        title: 'Kernarbeitszeiten gespeichert',
+        message:
+          'Die Tages- und Wochenansicht des Kalenders verwendet jetzt die neuen Zeiten.',
+        variant: 'success',
+      })
+    } catch (error) {
+      showErrorToast({
+        title: 'Kernarbeitszeiten konnten nicht gespeichert werden',
+        error,
+        fallback: 'Kernarbeitszeiten konnten nicht gespeichert werden',
+      })
+    } finally {
+      setIsSaving(false)
+    }
+  }
+
+  if (isLoading) {
+    return (
+      <div className="rounded-2xl bg-white p-6 text-sm text-gray-500 shadow-sm ring-1 ring-gray-200 dark:bg-gray-900 dark:text-gray-400 dark:ring-white/10">
+        Kalender-Einstellungen werden geladen...
+      </div>
+    )
+  }
+
+  return (
+    <div className="grid grid-cols-1 gap-x-10 gap-y-8 xl:grid-cols-[minmax(0,20rem)_minmax(0,1fr)]">
+      <div>
+        <div className="flex size-10 items-center justify-center rounded-xl bg-indigo-50 text-indigo-600 dark:bg-indigo-500/15 dark:text-indigo-300">
+          <ClockIcon className="size-5" />
+        </div>
+        <h2 className="mt-4 text-base font-semibold text-gray-900 dark:text-white">
+          Kernarbeitszeiten
+        </h2>
+        <p className="mt-2 text-sm/6 text-gray-500 dark:text-gray-400">
+          Lege für jeden Wochentag den hervorgehobenen Arbeitszeitraum fest.
+          Deaktivierte Tage erhalten im Kalender keine Markierung.
+        </p>
+      </div>
+
+      <form
+        onSubmit={handleSubmit}
+        className="overflow-hidden rounded-2xl bg-white shadow-sm ring-1 ring-gray-200 dark:bg-gray-900 dark:ring-white/10"
+      >
+        <div className="hidden grid-cols-[minmax(9rem,1fr)_auto_8.5rem_8.5rem] gap-4 border-b border-gray-200 bg-gray-50 px-5 py-3 text-xs font-semibold uppercase tracking-wide text-gray-500 sm:grid dark:border-white/10 dark:bg-white/5 dark:text-gray-400">
+          <span>Wochentag</span>
+          <span>Aktiv</span>
+          <span>Beginn</span>
+          <span>Ende</span>
+        </div>
+
+        <div className="divide-y divide-gray-200 dark:divide-white/10">
+          {calendarWeekdays.map((weekday) => {
+            const hours = settings.coreWorkingHours[weekday.key]
+
+            return (
+              <div
+                key={weekday.key}
+                className="grid grid-cols-2 items-center gap-4 px-5 py-4 sm:grid-cols-[minmax(9rem,1fr)_auto_8.5rem_8.5rem]"
+              >
+                <span className="font-medium text-gray-900 dark:text-white">
+                  {weekday.label}
+                </span>
+                <Switch
+                  variant="short"
+                  checked={hours.enabled}
+                  aria-label={`${weekday.label} aktivieren`}
+                  onChange={(event) =>
+                    setSettings((current) => ({
+                      ...current,
+                      coreWorkingHours: {
+                        ...current.coreWorkingHours,
+                        [weekday.key]: {
+                          ...hours,
+                          enabled: event.target.checked,
+                        },
+                      },
+                    }))
+                  }
+                />
+                <label className="space-y-1 sm:space-y-0">
+                  <span className="block text-xs font-medium text-gray-500 sm:sr-only">
+                    Beginn
+                  </span>
+                  <input
+                    type="time"
+                    step={1800}
+                    value={hours.start}
+                    disabled={!hours.enabled}
+                    aria-label={`${weekday.label} Beginn`}
+                    onChange={(event) =>
+                      setSettings((current) => ({
+                        ...current,
+                        coreWorkingHours: {
+                          ...current.coreWorkingHours,
+                          [weekday.key]: {
+                            ...hours,
+                            start: event.target.value,
+                          },
+                        },
+                      }))
+                    }
+                    className={timeInputClassName}
+                  />
+                </label>
+                <label className="space-y-1 sm:space-y-0">
+                  <span className="block text-xs font-medium text-gray-500 sm:sr-only">
+                    Ende
+                  </span>
+                  <input
+                    type="time"
+                    step={1800}
+                    value={hours.end}
+                    disabled={!hours.enabled}
+                    aria-label={`${weekday.label} Ende`}
+                    onChange={(event) =>
+                      setSettings((current) => ({
+                        ...current,
+                        coreWorkingHours: {
+                          ...current.coreWorkingHours,
+                          [weekday.key]: {
+                            ...hours,
+                            end: event.target.value,
+                          },
+                        },
+                      }))
+                    }
+                    className={timeInputClassName}
+                  />
+                </label>
+              </div>
+            )
+          })}
+        </div>
+
+        <div className="border-t border-gray-200 bg-gray-50 px-5 py-4 dark:border-white/10 dark:bg-white/5">
+          {formError && (
+            <p className="mb-3 text-sm font-medium text-red-600 dark:text-red-300">
+              {formError}
+            </p>
+          )}
+          <Button type="submit" isLoading={isSaving}>
+            Kernarbeitszeiten speichern
+          </Button>
+        </div>
+      </form>
+    </div>
+  )
+}

frontend/src/pages/administration/chats/ChatsAdministration.tsx

@@ -0,0 +1,50 @@
+import { Navigate, useLocation } from 'react-router'
+import Tabs from '../../../components/Tabs'
+import ChannelsAdministration from '../channels/ChannelsAdministration'
+import GroupChatsAdministration from '../groups/GroupChatsAdministration'
+import TeamsAdministration from '../teams/TeamsAdministration'
+
+const sections = ['teams', 'gruppen', 'channels'] as const
+
+export default function ChatsAdministration() {
+  const location = useLocation()
+  const section = location.pathname.split('/').filter(Boolean)[2] ?? 'teams'
+
+  if (!sections.includes(section as (typeof sections)[number])) {
+    return <Navigate to="/administration/chats/teams" replace />
+  }
+
+  const tabs = [
+    {
+      name: 'Teams',
+      href: '/administration/chats/teams',
+      current: section === 'teams',
+    },
+    {
+      name: 'Gruppenchats',
+      href: '/administration/chats/gruppen',
+      current: section === 'gruppen',
+    },
+    {
+      name: 'Channels',
+      href: '/administration/chats/channels',
+      current: section === 'channels',
+    },
+  ]
+
+  return (
+    <section>
+      <div className="mb-6">
+        <Tabs
+          tabs={tabs}
+          variant="bar-underline"
+          ariaLabel="Teams und Chats"
+        />
+      </div>
+
+      {section === 'teams' && <TeamsAdministration />}
+      {section === 'gruppen' && <GroupChatsAdministration />}
+      {section === 'channels' && <ChannelsAdministration />}
+    </section>
+  )
+}

frontend/src/pages/administration/groups/GroupChatsAdministration.tsx

@@ -0,0 +1,529 @@
+import {
+  useCallback,
+  useEffect,
+  useMemo,
+  useRef,
+  useState,
+  type ChangeEvent,
+  type FormEvent,
+} from 'react'
+import {
+  MagnifyingGlassIcon,
+  PhotoIcon,
+  TrashIcon,
+  UserGroupIcon,
+} from '@heroicons/react/20/solid'
+import Avatar from '../../../components/Avatar'
+import Button from '../../../components/Button'
+import Checkbox from '../../../components/Checkbox'
+import LoadingSpinner from '../../../components/LoadingSpinner'
+import { useNotifications } from '../../../components/Notifications'
+
+const API_URL = import.meta.env.VITE_API_URL ?? 'http://localhost:8080'
+
+type AdminGroupChat = {
+  id: string
+  name: string
+  image: string
+  ownerId: string
+  userIds: string[]
+  createdAt: string
+  updatedAt: string
+}
+
+type AdminGroupUser = {
+  id: string
+  username: string
+  displayName: string
+  email: string
+  unit: string
+}
+
+type GroupDraft = {
+  id: string
+  name: string
+  image: string
+  ownerId: string
+  userIds: string[]
+}
+
+const inputClassName =
+  'block w-full rounded-md bg-white px-3 py-1.5 text-sm 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 dark:bg-white/5 dark:text-white dark:outline-white/10 dark:focus:outline-indigo-500'
+
+async function readApiError(response: Response, fallback: string) {
+  const data = await response.json().catch(() => null)
+  return data?.error ?? fallback
+}
+
+function userDisplayName(user: AdminGroupUser) {
+  return user.displayName || user.username || user.email
+}
+
+function groupToDraft(group: AdminGroupChat): GroupDraft {
+  return {
+    id: group.id,
+    name: group.name,
+    image: group.image,
+    ownerId: group.ownerId,
+    userIds: group.userIds ?? [],
+  }
+}
+
+export default function GroupChatsAdministration() {
+  const { showToast, showErrorToast } = useNotifications()
+  const [groups, setGroups] = useState<AdminGroupChat[]>([])
+  const [users, setUsers] = useState<AdminGroupUser[]>([])
+  const [draft, setDraft] = useState<GroupDraft | null>(null)
+  const [groupSearch, setGroupSearch] = useState('')
+  const [userSearch, setUserSearch] = useState('')
+  const [isLoading, setIsLoading] = useState(true)
+  const [isSaving, setIsSaving] = useState(false)
+  const [isDeleting, setIsDeleting] = useState(false)
+  const imageInputRef = useRef<HTMLInputElement | null>(null)
+
+  const loadGroups = useCallback(
+    async (preferredId?: string) => {
+      setIsLoading(true)
+      try {
+        const response = await fetch(`${API_URL}/admin/group-chats`, {
+          credentials: 'include',
+        })
+        if (!response.ok) {
+          throw new Error(
+            await readApiError(
+              response,
+              'Gruppenchats konnten nicht geladen werden',
+            ),
+          )
+        }
+
+        const data = await response.json()
+        const nextGroups = (data.groups ?? []) as AdminGroupChat[]
+        setGroups(nextGroups)
+        setUsers(data.users ?? [])
+
+        const selected =
+          nextGroups.find((group) => group.id === preferredId) ??
+          nextGroups[0] ??
+          null
+        setDraft(selected ? groupToDraft(selected) : null)
+      } catch (error) {
+        showErrorToast({
+          title: 'Gruppenchats konnten nicht geladen werden',
+          error,
+          fallback: 'Gruppenchats konnten nicht geladen werden',
+        })
+      } finally {
+        setIsLoading(false)
+      }
+    },
+    [showErrorToast],
+  )
+
+  useEffect(() => {
+    const timeoutId = window.setTimeout(() => {
+      void loadGroups()
+    }, 0)
+
+    return () => window.clearTimeout(timeoutId)
+  }, [loadGroups])
+
+  const filteredGroups = useMemo(() => {
+    const search = groupSearch.trim().toLowerCase()
+    if (!search) {
+      return groups
+    }
+    return groups.filter((group) => group.name.toLowerCase().includes(search))
+  }, [groupSearch, groups])
+
+  const filteredUsers = useMemo(() => {
+    const search = userSearch.trim().toLowerCase()
+    if (!search) {
+      return users
+    }
+    return users.filter((user) =>
+      [
+        user.displayName,
+        user.username,
+        user.email,
+        user.unit,
+      ]
+        .join(' ')
+        .toLowerCase()
+        .includes(search),
+    )
+  }, [userSearch, users])
+
+  const owner = users.find((user) => user.id === draft?.ownerId)
+
+  function selectGroup(group: AdminGroupChat) {
+    setDraft(groupToDraft(group))
+    setUserSearch('')
+  }
+
+  function updateDraft<Key extends keyof GroupDraft>(
+    key: Key,
+    value: GroupDraft[Key],
+  ) {
+    setDraft((current) => (current ? { ...current, [key]: value } : current))
+  }
+
+  function toggleUser(userId: string, checked: boolean) {
+    if (!draft || userId === draft.ownerId) {
+      return
+    }
+
+    updateDraft(
+      'userIds',
+      checked
+        ? [...new Set([...draft.userIds, userId])]
+        : draft.userIds.filter((id) => id !== userId),
+    )
+  }
+
+  function handleImageFileChange(event: ChangeEvent<HTMLInputElement>) {
+    const file = event.target.files?.[0]
+    event.target.value = ''
+
+    if (!file) {
+      return
+    }
+    if (!file.type.startsWith('image/')) {
+      showToast({
+        title: 'Ungültige Bilddatei',
+        message: 'Bitte wähle eine gültige Bilddatei aus.',
+        variant: 'error',
+      })
+      return
+    }
+    if (file.size > 3 * 1024 * 1024) {
+      showToast({
+        title: 'Gruppenbild zu groß',
+        message: 'Das Gruppenbild darf maximal 3 MB groß sein.',
+        variant: 'error',
+      })
+      return
+    }
+
+    const reader = new FileReader()
+    reader.onload = () => {
+      if (typeof reader.result === 'string') {
+        updateDraft('image', reader.result)
+      }
+    }
+    reader.readAsDataURL(file)
+  }
+
+  async function saveGroup(event: FormEvent<HTMLFormElement>) {
+    event.preventDefault()
+    if (!draft) {
+      return
+    }
+
+    setIsSaving(true)
+    try {
+      const response = await fetch(`${API_URL}/admin/group-chats/${draft.id}`, {
+        method: 'PUT',
+        credentials: 'include',
+        headers: { 'Content-Type': 'application/json' },
+        body: JSON.stringify({
+          name: draft.name,
+          image: draft.image,
+          userIds: draft.userIds,
+        }),
+      })
+      if (!response.ok) {
+        throw new Error(
+          await readApiError(
+            response,
+            'Gruppenchat konnte nicht gespeichert werden',
+          ),
+        )
+      }
+
+      await loadGroups(draft.id)
+      showToast({
+        title: 'Gruppenchat gespeichert',
+        message: 'Name, Bild und Mitglieder wurden aktualisiert.',
+        variant: 'success',
+      })
+    } catch (error) {
+      showErrorToast({
+        title: 'Gruppenchat konnte nicht gespeichert werden',
+        error,
+        fallback: 'Gruppenchat konnte nicht gespeichert werden',
+      })
+    } finally {
+      setIsSaving(false)
+    }
+  }
+
+  async function deleteGroup() {
+    if (
+      !draft ||
+      !window.confirm(
+        `Möchtest du den Gruppenchat „${draft.name}“ wirklich löschen? Alle Nachrichten und Anhänge werden dauerhaft gelöscht.`,
+      )
+    ) {
+      return
+    }
+
+    setIsDeleting(true)
+    try {
+      const response = await fetch(`${API_URL}/admin/group-chats/${draft.id}`, {
+        method: 'DELETE',
+        credentials: 'include',
+      })
+      if (!response.ok) {
+        throw new Error(
+          await readApiError(
+            response,
+            'Gruppenchat konnte nicht gelöscht werden',
+          ),
+        )
+      }
+
+      await loadGroups()
+      showToast({
+        title: 'Gruppenchat gelöscht',
+        message: 'Der Gruppenchat und sein Verlauf wurden dauerhaft gelöscht.',
+        variant: 'success',
+      })
+    } catch (error) {
+      showErrorToast({
+        title: 'Gruppenchat konnte nicht gelöscht werden',
+        error,
+        fallback: 'Gruppenchat konnte nicht gelöscht werden',
+      })
+    } finally {
+      setIsDeleting(false)
+    }
+  }
+
+  if (isLoading) {
+    return (
+      <div className="rounded-xl bg-white p-8 shadow-sm ring-1 ring-gray-200 dark:bg-gray-900 dark:ring-white/10">
+        <LoadingSpinner label="Gruppenchats werden geladen..." center />
+      </div>
+    )
+  }
+
+  if (!draft) {
+    return (
+      <div className="rounded-xl bg-white p-8 text-center shadow-sm ring-1 ring-gray-200 dark:bg-gray-900 dark:ring-white/10">
+        <UserGroupIcon className="mx-auto size-10 text-gray-300 dark:text-gray-600" />
+        <h2 className="mt-3 text-sm font-semibold text-gray-900 dark:text-white">
+          Keine freien Gruppenchats
+        </h2>
+        <p className="mt-1 text-sm text-gray-500 dark:text-gray-400">
+          Neue Gruppenchats werden im Chat erstellt und können anschließend hier
+          administriert werden.
+        </p>
+      </div>
+    )
+  }
+
+  return (
+    <div className="grid grid-cols-1 gap-6 xl:grid-cols-[19rem_minmax(0,1fr)]">
+      <aside className="overflow-hidden rounded-xl bg-white shadow-sm ring-1 ring-gray-200 dark:bg-gray-900 dark:ring-white/10">
+        <div className="border-b border-gray-200 p-4 dark:border-white/10">
+          <h2 className="text-sm font-semibold text-gray-900 dark:text-white">
+            Gruppenchats
+          </h2>
+          <p className="mt-1 text-xs text-gray-500 dark:text-gray-400">
+            {filteredGroups.length} von {groups.length} angezeigt
+          </p>
+
+          <div className="relative mt-4">
+            <MagnifyingGlassIcon
+              aria-hidden="true"
+              className="pointer-events-none absolute top-1/2 left-3 size-4 -translate-y-1/2 text-gray-400"
+            />
+            <input
+              type="search"
+              value={groupSearch}
+              onChange={(event) => setGroupSearch(event.target.value)}
+              placeholder="Gruppenchats suchen..."
+              className={`${inputClassName} pl-9`}
+            />
+          </div>
+        </div>
+
+        <div className="max-h-[calc(100dvh-22rem)] space-y-1 overflow-y-auto p-2">
+          {filteredGroups.map((group) => (
+            <button
+              key={group.id}
+              type="button"
+              onClick={() => selectGroup(group)}
+              className={`flex w-full items-center gap-3 rounded-lg px-3 py-2.5 text-left text-sm ${
+                draft.id === group.id
+                  ? 'bg-indigo-50 text-indigo-700 dark:bg-indigo-500/10 dark:text-indigo-300'
+                  : 'text-gray-700 hover:bg-gray-50 dark:text-gray-300 dark:hover:bg-white/5'
+              }`}
+            >
+              <Avatar
+                src={group.image}
+                name={group.name}
+                size={9}
+                shape="rounded"
+              />
+              <span className="min-w-0">
+                <span className="block truncate font-medium">{group.name}</span>
+                <span className="block truncate text-xs opacity-70">
+                  {group.userIds.length} Mitglieder
+                </span>
+              </span>
+            </button>
+          ))}
+        </div>
+      </aside>
+
+      <form
+        onSubmit={saveGroup}
+        className="rounded-xl bg-white p-5 shadow-sm ring-1 ring-gray-200 dark:bg-gray-900 dark:ring-white/10"
+      >
+        <div>
+          <h2 className="text-base font-semibold text-gray-900 dark:text-white">
+            Gruppenchat bearbeiten
+          </h2>
+          <p className="mt-1 text-sm text-gray-500 dark:text-gray-400">
+            Der Ersteller bleibt Mitglied; weitere Mitglieder können zentral
+            verwaltet werden.
+          </p>
+        </div>
+
+        <div className="mt-5">
+          <label className="text-sm font-medium text-gray-900 dark:text-white">
+            Gruppenname
+            <input
+              required
+              maxLength={80}
+              value={draft.name}
+              onChange={(event) => updateDraft('name', event.target.value)}
+              className={`${inputClassName} mt-2`}
+            />
+          </label>
+        </div>
+
+        <div className="mt-5">
+          <p className="text-sm font-medium text-gray-900 dark:text-white">
+            Gruppenbild
+          </p>
+          <div className="mt-2 flex items-center gap-4">
+            <Avatar
+              src={draft.image}
+              name={draft.name || 'Gruppenchat'}
+              size={14}
+              shape="rounded"
+            />
+            <div>
+              <input
+                ref={imageInputRef}
+                type="file"
+                accept="image/png,image/jpeg,image/webp,image/gif"
+                className="sr-only"
+                onChange={handleImageFileChange}
+              />
+              <div className="flex flex-wrap gap-2">
+                <Button
+                  type="button"
+                  variant="secondary"
+                  color="gray"
+                  size="sm"
+                  leadingIcon={<PhotoIcon className="size-4" />}
+                  onClick={() => imageInputRef.current?.click()}
+                >
+                  Bild hochladen
+                </Button>
+                {draft.image && (
+                  <Button
+                    type="button"
+                    variant="secondary"
+                    color="red"
+                    size="sm"
+                    onClick={() => updateDraft('image', '')}
+                  >
+                    Entfernen
+                  </Button>
+                )}
+              </div>
+              <p className="mt-2 text-xs text-gray-500 dark:text-gray-400">
+                Optional: PNG, JPG, WEBP oder GIF bis maximal 3 MB.
+              </p>
+            </div>
+          </div>
+        </div>
+
+        <div className="mt-6 border-t border-gray-200 pt-5 dark:border-white/10">
+          <div className="flex flex-wrap items-end justify-between gap-3">
+            <div>
+              <h3 className="text-sm font-medium text-gray-900 dark:text-white">
+                Mitglieder
+              </h3>
+              <p className="mt-1 text-xs text-gray-500 dark:text-gray-400">
+                Ersteller: {owner ? userDisplayName(owner) : 'Unbekannt'}
+              </p>
+            </div>
+            <div className="relative w-full sm:w-64">
+              <MagnifyingGlassIcon
+                aria-hidden="true"
+                className="pointer-events-none absolute top-1/2 left-3 size-4 -translate-y-1/2 text-gray-400"
+              />
+              <input
+                type="search"
+                value={userSearch}
+                onChange={(event) => setUserSearch(event.target.value)}
+                placeholder="Mitglieder suchen..."
+                className={`${inputClassName} pl-9`}
+              />
+            </div>
+          </div>
+
+          <div className="mt-3 grid max-h-72 gap-2 overflow-y-auto rounded-lg border border-gray-200 p-3 sm:grid-cols-2 dark:border-white/10">
+            {filteredUsers.map((user) => {
+              const isOwner = user.id === draft.ownerId
+              return (
+                <Checkbox
+                  key={user.id}
+                  checked={isOwner || draft.userIds.includes(user.id)}
+                  disabled={isOwner}
+                  onChange={(event) =>
+                    toggleUser(user.id, event.target.checked)
+                  }
+                  label={
+                    isOwner
+                      ? `${userDisplayName(user)} (Ersteller)`
+                      : userDisplayName(user)
+                  }
+                  description={user.unit || user.email}
+                />
+              )
+            })}
+          </div>
+        </div>
+
+        <div className="mt-6 flex flex-wrap justify-between gap-3">
+          <Button
+            type="button"
+            variant="secondary"
+            color="red"
+            disabled={isSaving}
+            isLoading={isDeleting}
+            leadingIcon={<TrashIcon className="size-4" />}
+            onClick={() => void deleteGroup()}
+          >
+            Gruppenchat löschen
+          </Button>
+          <Button
+            type="submit"
+            color="indigo"
+            disabled={isDeleting}
+            isLoading={isSaving}
+          >
+            Gruppenchat speichern
+          </Button>
+        </div>
+      </form>
+    </div>
+  )
+}

frontend/src/pages/administration/teams/TeamsAdministration.tsx

@@ -16,6 +16,7 @@ type AdminTeam = {
   name: string
   initial: string
   href: string
+  conversationId: string
 }
 
 const inputClassName =
@@ -263,7 +264,9 @@ export default function TeamsAdministration() {
                         </span>
 
                         <span className="block truncate text-xs text-gray-500 dark:text-gray-400">
-                          {team.href || '#'}
+                          {team.conversationId
+                            ? 'Gruppenchat aktiv'
+                            : 'Gruppenchat wird vorbereitet'}
                         </span>
                       </span>
                     </button>
@@ -294,6 +297,11 @@ export default function TeamsAdministration() {
           </div>
 
           <div className="mt-4 space-y-4">
+            <div className="rounded-lg bg-indigo-50 p-4 text-sm text-indigo-800 ring-1 ring-indigo-100 dark:bg-indigo-500/10 dark:text-indigo-200 dark:ring-indigo-500/20">
+              Für jedes Team wird automatisch ein Gruppenchat mit allen
+              Teammitgliedern geführt.
+            </div>
+
             <div>
               <label
                 htmlFor="team-name"

frontend/src/pages/calendar/CalendarPage.tsx

@@ -0,0 +1,612 @@
+import { TrashIcon, XMarkIcon } from '@heroicons/react/24/outline'
+import { useEffect, useState, type FormEvent } from 'react'
+import Modal, { ModalTitle } from '../../components/Modal'
+import Calendar, {
+  type CalendarEvent,
+  type CalendarEventColor,
+  type CalendarView,
+} from '../../components/calendar/Calendar'
+import {
+  createDefaultCalendarSettings,
+  normalizeCalendarSettings,
+  type CalendarSettings,
+} from '../../components/calendar/calendarSettings'
+import { toDateKey } from '../../components/calendar/dateUtils'
+
+const STORAGE_KEY = 'teg.calendar.events.v1'
+const API_URL = import.meta.env.VITE_API_URL ?? 'http://localhost:8080'
+
+type EventDraft = {
+  title: string
+  startDate: string
+  endDate: string
+  startTime: string
+  endTime: string
+  allDay: boolean
+  location: string
+  description: string
+  color: CalendarEventColor
+}
+
+const colorOptions: Array<{
+  value: CalendarEventColor
+  label: string
+  className: string
+}> = [
+  { value: 'indigo', label: 'Indigo', className: 'bg-indigo-500' },
+  { value: 'blue', label: 'Blau', className: 'bg-blue-500' },
+  { value: 'emerald', label: 'Grün', className: 'bg-emerald-500' },
+  { value: 'amber', label: 'Gelb', className: 'bg-amber-500' },
+  { value: 'rose', label: 'Rot', className: 'bg-rose-500' },
+  { value: 'slate', label: 'Grau', className: 'bg-slate-500' },
+]
+
+function classNames(...classes: Array<string | false | null | undefined>) {
+  return classes.filter(Boolean).join(' ')
+}
+
+function dateAt(date: Date, hour: number, minute = 0) {
+  return new Date(
+    date.getFullYear(),
+    date.getMonth(),
+    date.getDate(),
+    hour,
+    minute,
+  )
+}
+
+function toLocalDateTime(date: Date) {
+  const hours = String(date.getHours()).padStart(2, '0')
+  const minutes = String(date.getMinutes()).padStart(2, '0')
+  return `${toDateKey(date)}T${hours}:${minutes}`
+}
+
+function createSeedEvents() {
+  const today = new Date()
+  const tomorrow = new Date(today)
+  tomorrow.setDate(tomorrow.getDate() + 1)
+  const later = new Date(today)
+  later.setDate(later.getDate() + 3)
+
+  return [
+    {
+      id: 'welcome-team',
+      title: 'Teambesprechung',
+      start: toLocalDateTime(dateAt(today, 10)),
+      end: toLocalDateTime(dateAt(today, 11)),
+      allDay: false,
+      location: 'Besprechungsraum 1',
+      description: 'Kurze Abstimmung zu den aktuellen Aufgaben.',
+      color: 'indigo',
+    },
+    {
+      id: 'welcome-planning',
+      title: 'Einsatzplanung',
+      start: toLocalDateTime(dateAt(tomorrow, 14)),
+      end: toLocalDateTime(dateAt(tomorrow, 15, 30)),
+      allDay: false,
+      location: 'Leitstelle',
+      description: '',
+      color: 'blue',
+    },
+    {
+      id: 'welcome-maintenance',
+      title: 'Wartungsfenster',
+      start: toLocalDateTime(dateAt(later, 0)),
+      end: toLocalDateTime(dateAt(later, 23, 59)),
+      allDay: true,
+      location: '',
+      description: 'Geplante Wartung der Infrastruktur.',
+      color: 'amber',
+    },
+  ] satisfies CalendarEvent[]
+}
+
+function loadEvents() {
+  try {
+    const stored = window.localStorage.getItem(STORAGE_KEY)
+    if (!stored) {
+      return createSeedEvents()
+    }
+
+    const parsed = JSON.parse(stored)
+    return Array.isArray(parsed) ? (parsed as CalendarEvent[]) : createSeedEvents()
+  } catch {
+    return createSeedEvents()
+  }
+}
+
+function timeFromMinutes(minutes: number) {
+  return `${String(Math.floor(minutes / 60)).padStart(2, '0')}:${String(
+    minutes % 60,
+  ).padStart(2, '0')}`
+}
+
+function emptyDraft(start: Date, end?: Date, allDay = false): EventDraft {
+  const now = new Date()
+  const isToday = toDateKey(start) === toDateKey(now)
+  const proposedHour = isToday
+    ? Math.min(22, Math.max(8, now.getHours() + 1))
+    : 9
+  const startMinutes = end
+    ? start.getHours() * 60 + start.getMinutes()
+    : proposedHour * 60
+  const resolvedEnd = end ?? new Date(start)
+
+  if (!end) {
+    resolvedEnd.setHours(0, startMinutes + 30, 0, 0)
+  }
+  const endMinutes = resolvedEnd.getHours() * 60 + resolvedEnd.getMinutes()
+
+  return {
+    title: '',
+    startDate: toDateKey(start),
+    endDate: toDateKey(resolvedEnd),
+    startTime: timeFromMinutes(startMinutes),
+    endTime: timeFromMinutes(endMinutes),
+    allDay,
+    location: '',
+    description: '',
+    color: 'indigo',
+  }
+}
+
+function eventToDraft(event: CalendarEvent): EventDraft {
+  const start = new Date(event.start)
+  const end = new Date(event.end)
+
+  return {
+    title: event.title,
+    startDate: toDateKey(start),
+    endDate: toDateKey(end),
+    startTime: `${String(start.getHours()).padStart(2, '0')}:${String(
+      start.getMinutes(),
+    ).padStart(2, '0')}`,
+    endTime: `${String(end.getHours()).padStart(2, '0')}:${String(
+      end.getMinutes(),
+    ).padStart(2, '0')}`,
+    allDay: event.allDay,
+    location: event.location,
+    description: event.description,
+    color: event.color,
+  }
+}
+
+function createEventId() {
+  return typeof crypto.randomUUID === 'function'
+    ? crypto.randomUUID()
+    : `event-${Date.now()}`
+}
+
+export default function CalendarPage() {
+  const [events, setEvents] = useState<CalendarEvent[]>(loadEvents)
+  const [calendarSettings, setCalendarSettings] = useState<CalendarSettings>(
+    createDefaultCalendarSettings,
+  )
+  const [selectedDate, setSelectedDate] = useState(() => new Date())
+  const [view, setView] = useState<CalendarView>('month')
+  const [editingEvent, setEditingEvent] = useState<CalendarEvent | null>(null)
+  const [editorOpen, setEditorOpen] = useState(false)
+  const [draft, setDraft] = useState<EventDraft>(() => emptyDraft(new Date()))
+  const [formError, setFormError] = useState('')
+
+  useEffect(() => {
+    window.localStorage.setItem(STORAGE_KEY, JSON.stringify(events))
+  }, [events])
+
+  useEffect(() => {
+    let ignore = false
+
+    void fetch(`${API_URL}/calendar/settings`, {
+      credentials: 'include',
+    })
+      .then(async (response) => {
+        if (!response.ok) {
+          return null
+        }
+
+        return response.json()
+      })
+      .then((data) => {
+        if (!ignore && data?.settings) {
+          setCalendarSettings(normalizeCalendarSettings(data.settings))
+        }
+      })
+      .catch(() => undefined)
+
+    return () => {
+      ignore = true
+    }
+  }, [])
+
+  function openCreate(start: Date, end?: Date, allDay?: boolean) {
+    setEditingEvent(null)
+    setDraft(emptyDraft(start, end, allDay))
+    setFormError('')
+    setEditorOpen(true)
+  }
+
+  function openEdit(event: CalendarEvent) {
+    setEditingEvent(event)
+    setDraft(eventToDraft(event))
+    setFormError('')
+    setEditorOpen(true)
+  }
+
+  function closeEditor() {
+    setEditorOpen(false)
+    setEditingEvent(null)
+    setFormError('')
+  }
+
+  function saveEvent(event: FormEvent<HTMLFormElement>) {
+    event.preventDefault()
+
+    const title = draft.title.trim()
+    if (!title) {
+      setFormError('Bitte gib einen Titel ein.')
+      return
+    }
+
+    const start = draft.allDay
+      ? `${draft.startDate}T00:00`
+      : `${draft.startDate}T${draft.startTime}`
+    let end = draft.allDay
+      ? `${draft.endDate}T23:59`
+      : `${draft.endDate}T${draft.endTime}`
+
+    if (new Date(end).getTime() <= new Date(start).getTime()) {
+      if (draft.allDay) {
+        end = `${draft.endDate}T23:59`
+      } else {
+        setFormError('Das Ende muss nach dem Beginn liegen.')
+        return
+      }
+    }
+
+    const nextEvent: CalendarEvent = {
+      id: editingEvent?.id ?? createEventId(),
+      title,
+      start,
+      end,
+      allDay: draft.allDay,
+      location: draft.location.trim(),
+      description: draft.description.trim(),
+      color: draft.color,
+    }
+
+    setEvents((current) =>
+      editingEvent
+        ? current.map((item) =>
+            item.id === editingEvent.id ? nextEvent : item,
+          )
+        : [...current, nextEvent],
+    )
+    setSelectedDate(new Date(start))
+    closeEditor()
+  }
+
+  function deleteEvent() {
+    if (
+      !editingEvent ||
+      !window.confirm(`Termin „${editingEvent.title}“ wirklich löschen?`)
+    ) {
+      return
+    }
+
+    setEvents((current) =>
+      current.filter((event) => event.id !== editingEvent.id),
+    )
+    closeEditor()
+  }
+
+  const inputClassName =
+    'block w-full rounded-xl border-0 bg-gray-100 px-3 py-2.5 text-sm text-gray-900 outline-none ring-1 ring-transparent focus:bg-white focus:ring-indigo-500 dark:bg-white/5 dark:text-white dark:focus:bg-white/10'
+
+  return (
+    <>
+      <div className="h-full min-h-0">
+        <Calendar
+          events={events}
+          coreWorkingHours={calendarSettings.coreWorkingHours}
+          selectedDate={selectedDate}
+          view={view}
+          onSelectedDateChange={setSelectedDate}
+          onViewChange={setView}
+          onCreateEvent={openCreate}
+          onEditEvent={openEdit}
+        />
+      </div>
+
+      <Modal
+        open={editorOpen}
+        setOpen={(open) => {
+          if (!open) {
+            closeEditor()
+          }
+        }}
+        zIndexClassName="z-[10000]"
+        backdropClassName="bg-gray-950/60 backdrop-blur-sm dark:bg-gray-950/60"
+        panelClassName="max-h-[min(48rem,90vh)] max-w-xl rounded-2xl bg-white dark:bg-gray-900"
+      >
+        <form onSubmit={saveEvent} className="max-h-[min(48rem,90vh)] overflow-y-auto">
+                <div className="flex items-center justify-between border-b border-gray-200 px-5 py-4 dark:border-white/10">
+                  <ModalTitle>
+                    {editingEvent ? 'Termin bearbeiten' : 'Neuer Termin'}
+                  </ModalTitle>
+                  <button
+                    type="button"
+                    onClick={closeEditor}
+                    className="inline-flex size-8 items-center justify-center rounded-full text-gray-400 hover:bg-gray-100 hover:text-gray-600 dark:hover:bg-white/10 dark:hover:text-white"
+                  >
+                    <span className="sr-only">Schließen</span>
+                    <XMarkIcon className="size-5" />
+                  </button>
+                </div>
+
+                <div className="space-y-5 p-5">
+                  <div>
+                    <label
+                      htmlFor="calendar-title"
+                      className="block text-sm font-medium text-gray-900 dark:text-white"
+                    >
+                      Titel
+                    </label>
+                    <input
+                      id="calendar-title"
+                      autoFocus
+                      value={draft.title}
+                      onChange={(event) =>
+                        setDraft((current) => ({
+                          ...current,
+                          title: event.target.value,
+                        }))
+                      }
+                      className={classNames(inputClassName, 'mt-2')}
+                      placeholder="Was steht an?"
+                      maxLength={120}
+                    />
+                  </div>
+
+                  <div className="grid grid-cols-1 gap-4 sm:grid-cols-2">
+                    <div>
+                      <label
+                        htmlFor="calendar-start-date"
+                        className="block text-sm font-medium text-gray-900 dark:text-white"
+                      >
+                        Startdatum
+                      </label>
+                      <input
+                        id="calendar-start-date"
+                        type="date"
+                        value={draft.startDate}
+                        onChange={(event) =>
+                          setDraft((current) => {
+                            const startDate = event.target.value
+                            return {
+                              ...current,
+                              startDate,
+                              endDate:
+                                current.endDate < startDate
+                                  ? startDate
+                                  : current.endDate,
+                            }
+                          })
+                        }
+                        className={classNames(inputClassName, 'mt-2')}
+                      />
+                    </div>
+                    <div>
+                      <label
+                        htmlFor="calendar-start"
+                        className="block text-sm font-medium text-gray-900 dark:text-white"
+                      >
+                        Beginn
+                      </label>
+                      <input
+                        id="calendar-start"
+                        type="time"
+                        value={draft.startTime}
+                        disabled={draft.allDay}
+                        onChange={(event) =>
+                          setDraft((current) => ({
+                            ...current,
+                            startTime: event.target.value,
+                          }))
+                        }
+                        className={classNames(
+                          inputClassName,
+                          'mt-2 disabled:cursor-not-allowed disabled:opacity-50',
+                        )}
+                      />
+                    </div>
+                    <div>
+                      <label
+                        htmlFor="calendar-end-date"
+                        className="block text-sm font-medium text-gray-900 dark:text-white"
+                      >
+                        Enddatum
+                      </label>
+                      <input
+                        id="calendar-end-date"
+                        type="date"
+                        min={draft.startDate}
+                        value={draft.endDate}
+                        onChange={(event) =>
+                          setDraft((current) => ({
+                            ...current,
+                            endDate: event.target.value,
+                          }))
+                        }
+                        className={classNames(inputClassName, 'mt-2')}
+                      />
+                    </div>
+                    <div>
+                      <label
+                        htmlFor="calendar-end"
+                        className="block text-sm font-medium text-gray-900 dark:text-white"
+                      >
+                        Ende
+                      </label>
+                      <input
+                        id="calendar-end"
+                        type="time"
+                        value={draft.endTime}
+                        disabled={draft.allDay}
+                        onChange={(event) =>
+                          setDraft((current) => ({
+                            ...current,
+                            endTime: event.target.value,
+                          }))
+                        }
+                        className={classNames(
+                          inputClassName,
+                          'mt-2 disabled:cursor-not-allowed disabled:opacity-50',
+                        )}
+                      />
+                    </div>
+                  </div>
+
+                  <label className="flex cursor-pointer items-center gap-3 rounded-xl bg-gray-50 px-3 py-2.5 ring-1 ring-gray-200 dark:bg-white/5 dark:ring-white/10">
+                    <input
+                      type="checkbox"
+                      checked={draft.allDay}
+                      onChange={(event) =>
+                        setDraft((current) => ({
+                          ...current,
+                          allDay: event.target.checked,
+                        }))
+                      }
+                      className="size-4 rounded border-gray-300 text-indigo-600 focus:ring-indigo-500"
+                    />
+                    <span className="text-sm font-medium text-gray-700 dark:text-gray-200">
+                      Ganztägiger Termin
+                    </span>
+                  </label>
+
+                  <div>
+                    <label
+                      htmlFor="calendar-location"
+                      className="block text-sm font-medium text-gray-900 dark:text-white"
+                    >
+                      Ort
+                    </label>
+                    <input
+                      id="calendar-location"
+                      value={draft.location}
+                      onChange={(event) =>
+                        setDraft((current) => ({
+                          ...current,
+                          location: event.target.value,
+                        }))
+                      }
+                      className={classNames(inputClassName, 'mt-2')}
+                      placeholder="Optional"
+                      maxLength={160}
+                    />
+                  </div>
+
+                  <div>
+                    <label
+                      htmlFor="calendar-description"
+                      className="block text-sm font-medium text-gray-900 dark:text-white"
+                    >
+                      Beschreibung
+                    </label>
+                    <textarea
+                      id="calendar-description"
+                      rows={3}
+                      value={draft.description}
+                      onChange={(event) =>
+                        setDraft((current) => ({
+                          ...current,
+                          description: event.target.value,
+                        }))
+                      }
+                      className={classNames(inputClassName, 'mt-2 resize-none')}
+                      placeholder="Notizen zum Termin"
+                      maxLength={1000}
+                    />
+                  </div>
+
+                  <fieldset>
+                    <legend className="text-sm font-medium text-gray-900 dark:text-white">
+                      Farbe
+                    </legend>
+                    <div className="mt-2 flex flex-wrap gap-2">
+                      {colorOptions.map((color) => (
+                        <label
+                          key={color.value}
+                          title={color.label}
+                          className={classNames(
+                            'flex size-9 cursor-pointer items-center justify-center rounded-full ring-2 ring-offset-2 ring-offset-white transition dark:ring-offset-gray-900',
+                            draft.color === color.value
+                              ? 'ring-gray-900 dark:ring-white'
+                              : 'ring-transparent hover:ring-gray-300 dark:hover:ring-white/30',
+                          )}
+                        >
+                          <input
+                            type="radio"
+                            name="color"
+                            value={color.value}
+                            checked={draft.color === color.value}
+                            onChange={() =>
+                              setDraft((current) => ({
+                                ...current,
+                                color: color.value,
+                              }))
+                            }
+                            className="sr-only"
+                          />
+                          <span
+                            className={classNames(
+                              'size-7 rounded-full',
+                              color.className,
+                            )}
+                          />
+                        </label>
+                      ))}
+                    </div>
+                  </fieldset>
+
+                  {formError && (
+                    <p className="rounded-xl bg-red-50 px-3 py-2 text-sm text-red-700 ring-1 ring-red-200 dark:bg-red-500/10 dark:text-red-300 dark:ring-red-500/20">
+                      {formError}
+                    </p>
+                  )}
+                </div>
+
+                <div className="flex items-center justify-between gap-3 border-t border-gray-200 bg-gray-50 px-5 py-4 dark:border-white/10 dark:bg-white/5">
+                  <div>
+                    {editingEvent && (
+                      <button
+                        type="button"
+                        onClick={deleteEvent}
+                        className="inline-flex items-center gap-1.5 rounded-lg px-3 py-2 text-sm font-semibold text-red-600 hover:bg-red-50 dark:text-red-300 dark:hover:bg-red-500/10"
+                      >
+                        <TrashIcon className="size-4" />
+                        Löschen
+                      </button>
+                    )}
+                  </div>
+                  <div className="flex items-center gap-2">
+                    <button
+                      type="button"
+                      onClick={closeEditor}
+                      className="rounded-lg px-3 py-2 text-sm font-semibold text-gray-600 hover:bg-gray-200 dark:text-gray-300 dark:hover:bg-white/10"
+                    >
+                      Abbrechen
+                    </button>
+                    <button
+                      type="submit"
+                      className="rounded-lg bg-indigo-600 px-4 py-2 text-sm font-semibold text-white shadow-xs hover:bg-indigo-500 dark:bg-indigo-500 dark:hover:bg-indigo-400"
+                    >
+                      {editingEvent ? 'Speichern' : 'Termin erstellen'}
+                    </button>
+                  </div>
+                </div>
+        </form>
+      </Modal>
+    </>
+  )
+}

frontend/src/pages/settings/benachrichtigungen/Benachrichtigungen.tsx

@@ -8,7 +8,7 @@ import {
 } from 'react'
 import {
   BellIcon,
-  EnvelopeIcon,
+  ComputerDesktopIcon,
   PlayIcon,
   SpeakerWaveIcon,
 } from '@heroicons/react/20/solid'
@@ -17,39 +17,41 @@ import LoadingSpinner from '../../../components/LoadingSpinner'
 import Switch from '../../../components/Switch'
 import Button from '../../../components/Button'
 import { useNotifications } from '../../../components/Notifications'
+import {
+  disablePushNotifications,
+  enablePushNotifications,
+  isPushNotificationSupported,
+  syncExistingPushSubscription,
+} from '../../../utils/pushNotifications'
 
 const API_URL = import.meta.env.VITE_API_URL ?? 'http://localhost:8080'
 
 type NotificationSoundName = 'default' | 'chime' | 'soft' | 'alert' | 'success'
 
 type NotificationSettings = {
-  inAppEnabled: boolean
   soundEnabled: boolean
   soundName: NotificationSoundName
   emailEnabled: boolean
-  operationUpdates: boolean
-  operationJournals: boolean
   deviceUpdates: boolean
   deviceJournals: boolean
-  systemMessages: boolean
   chatMessages: boolean
   channelMessages: boolean
   desktopEnabled: boolean
+  pushChatMessages: boolean
+  pushChannelMessages: boolean
 }
 
 const defaultSettings: NotificationSettings = {
-  inAppEnabled: true,
   soundEnabled: false,
   soundName: 'default',
   emailEnabled: false,
-  operationUpdates: true,
-  operationJournals: true,
   deviceUpdates: true,
   deviceJournals: true,
-  systemMessages: true,
   chatMessages: true,
   channelMessages: true,
   desktopEnabled: false,
+  pushChatMessages: true,
+  pushChannelMessages: true,
 }
 
 const notificationSounds: Array<{
@@ -151,12 +153,17 @@ export default function Benachrichtigungen() {
     useState<NotificationSettings>(defaultSettings)
   const [isLoading, setIsLoading] = useState(true)
   const [isSaving, setIsSaving] = useState(false)
+  const [isPushSubscribed, setIsPushSubscribed] = useState(false)
+  const pushSupported = isPushNotificationSupported()
 
   const settingsRef = useRef<NotificationSettings>(defaultSettings)
   const saveRequestIdRef = useRef(0)
 
   useEffect(() => {
     void loadSettings()
+    void syncExistingPushSubscription()
+      .then(setIsPushSubscribed)
+      .catch(() => setIsPushSubscribed(false))
   }, [])
 
   async function loadSettings() {
@@ -274,29 +281,31 @@ export default function Benachrichtigungen() {
   }
 
   async function enableDesktopNotifications() {
-    if (!('Notification' in window)) {
+    try {
-      showToast({
+      const subscribed = await enablePushNotifications()
-        title: 'Nicht unterstützt',
+      setIsPushSubscribed(subscribed)
-        message: 'Dieser Browser unterstützt keine Windows-Benachrichtigungen.',
+      updateSetting('desktopEnabled', true)
-        variant: 'warning',
+    } catch (error) {
+      showErrorToast({
+        title: 'Windows-Benachrichtigungen konnten nicht aktiviert werden',
+        error,
+        fallback: 'Windows-Benachrichtigungen konnten nicht aktiviert werden.',
       })
-      return
     }
+  }
 
-    const permission = await Notification.requestPermission()
+  async function disableDesktopNotifications() {
-    if (permission !== 'granted') {
+    try {
-      showToast({
+      await disablePushNotifications()
-        title: 'Berechtigung fehlt',
+      setIsPushSubscribed(false)
-        message: 'Windows-Benachrichtigungen wurden nicht freigegeben.',
+      updateSetting('desktopEnabled', false)
-        variant: 'warning',
+    } catch (error) {
+      showErrorToast({
+        title: 'Windows-Benachrichtigungen konnten nicht deaktiviert werden',
+        error,
+        fallback: 'Windows-Benachrichtigungen konnten nicht deaktiviert werden.',
       })
-      return
     }
-
-    updateSetting('desktopEnabled', true)
-    new Notification('TEG-Benachrichtigungen aktiviert', {
-      body: 'Neue Chat- und Channel-Nachrichten können jetzt auf Windows-Ebene angezeigt werden.',
-    })
   }
 
   if (isLoading) {
@@ -339,21 +348,11 @@ export default function Benachrichtigungen() {
               title="In-App-Benachrichtigungen"
               description="Steuere Hinweise, die direkt in der Anwendung angezeigt werden."
             >
-              <Switch
-                checked={settings.inAppEnabled}
-                onChange={(event) =>
-                  updateSetting('inAppEnabled', event.target.checked)
-                }
-                label="In der Anwendung anzeigen"
-                description="Zeigt Hinweise im Benachrichtigungscenter an."
-              />
-
               <Switch
                 checked={settings.soundEnabled}
                 onChange={(event) =>
                   updateSetting('soundEnabled', event.target.checked)
                 }
-                disabled={!settings.inAppEnabled}
                 label="Signalton abspielen"
                 description="Spielt einen kurzen Ton bei neuen Benachrichtigungen ab."
               />
@@ -370,7 +369,7 @@ export default function Benachrichtigungen() {
                   <select
                     id="notification-sound"
                     value={settings.soundName}
-                    disabled={!settings.inAppEnabled || !settings.soundEnabled}
+                    disabled={!settings.soundEnabled}
                     onChange={(event) =>
                       updateSetting(
                         'soundName',
@@ -391,7 +390,7 @@ export default function Benachrichtigungen() {
                     variant="secondary"
                     color="gray"
                     size="sm"
-                    disabled={!settings.inAppEnabled || !settings.soundEnabled}
+                    disabled={!settings.soundEnabled}
                     leadingIcon={<PlayIcon aria-hidden="true" className="size-4" />}
                     onClick={() => playNotificationSound(settings.soundName)}
                   >
@@ -405,38 +404,6 @@ export default function Benachrichtigungen() {
               </div>
             </NotificationCard>
 
-            <NotificationCard
-              icon={<EnvelopeIcon aria-hidden="true" className="size-5" />}
-              title="Windows-Benachrichtigungen"
-              description="Zeigt neue Chat- und Channel-Nachrichten außerhalb des Browserfensters an."
-            >
-              <Switch
-                checked={settings.desktopEnabled}
-                onChange={(event) => {
-                  if (event.target.checked) {
-                    void enableDesktopNotifications()
-                    return
-                  }
-                  updateSetting('desktopEnabled', false)
-                }}
-                label="Auf Windows-Ebene anzeigen"
-                description="Benötigt die Benachrichtigungsfreigabe des Browsers."
-              />
-
-              {typeof Notification !== 'undefined' &&
-                Notification.permission !== 'granted' && (
-                  <Button
-                    type="button"
-                    variant="secondary"
-                    color="indigo"
-                    size="sm"
-                    onClick={() => void enableDesktopNotifications()}
-                  >
-                    Berechtigung erteilen
-                  </Button>
-                )}
-            </NotificationCard>
-
             <NotificationCard
               icon={<SpeakerWaveIcon aria-hidden="true" className="size-5" />}
               title="Ereignisse"
@@ -459,36 +426,85 @@ export default function Benachrichtigungen() {
                 label="Channel-Nachrichten"
                 description="Zeigt eine Browser-Benachrichtigung bei neuen Meldungen aus Channels."
               />
+            </NotificationCard>
 
+            <NotificationCard
+              icon={<ComputerDesktopIcon aria-hidden="true" className="size-5" />}
+              title="Push-Benachrichtigungen"
+              description="Erhalte neue Nachrichten als Windows-Push, auch wenn kein Tab geöffnet ist."
+            >
               <Switch
-                checked={settings.operationUpdates}
+                checked={settings.desktopEnabled}
-                onChange={(event) =>
+                onChange={(event) => {
-                  updateSetting('operationUpdates', event.target.checked)
+                  if (event.target.checked) {
-                }
+                    void enableDesktopNotifications()
-                disabled={!settings.inAppEnabled && !settings.emailEnabled}
+                    return
-                label="Einsatzänderungen"
+                  }
-                description="Benachrichtigt dich, wenn Einsätze erstellt oder geändert werden."
+                  void disableDesktopNotifications()
+                }}
+                label="Auf diesem Gerät empfangen"
+                description="Registriert dieses Gerät für Hintergrund-Push, auch ohne geöffneten Tab."
               />
 
-              <Switch
+              {!pushSupported && (
-                checked={settings.operationJournals}
+                <p className="text-sm text-amber-700 dark:text-amber-300">
-                onChange={(event) =>
+                  Push-Benachrichtigungen benötigen HTTPS oder localhost
-                  updateSetting('operationJournals', event.target.checked)
+                  und einen Browser mit Web-Push-Unterstützung.
-                }
+                </p>
-                disabled={!settings.inAppEnabled && !settings.emailEnabled}
+              )}
-                label="Einsatz-Journal"
-                description="Benachrichtigt dich bei neuen Journal-Einträgen zu Einsätzen."
-              />
 
-              <Switch
+              {pushSupported &&
-                checked={settings.systemMessages}
+                settings.desktopEnabled &&
-                onChange={(event) =>
+                !isPushSubscribed && (
-                  updateSetting('systemMessages', event.target.checked)
+                  <Button
-                }
+                    type="button"
-                disabled={!settings.inAppEnabled && !settings.emailEnabled}
+                    variant="secondary"
-                label="Systemmeldungen"
+                    color="indigo"
-                description="Benachrichtigt dich bei wichtigen Systemhinweisen."
+                    size="sm"
-              />
+                    onClick={() => void enableDesktopNotifications()}
+                  >
+                    Auf diesem Gerät aktivieren
+                  </Button>
+                )}
+
+              {isPushSubscribed && (
+                <p className="text-sm text-emerald-700 dark:text-emerald-300">
+                  Dieses Gerät empfängt Push-Benachrichtigungen.
+                </p>
+              )}
+
+              <div className="border-t border-gray-200 pt-5 dark:border-white/10">
+                <p className="text-sm font-medium text-gray-900 dark:text-white">
+                  Welche Nachrichten als Push gesendet werden
+                </p>
+
+                <div className="mt-4 space-y-5">
+                  <Switch
+                    checked={settings.pushChatMessages}
+                    onChange={(event) =>
+                      updateSetting('pushChatMessages', event.target.checked)
+                    }
+                    disabled={!pushSupported || !settings.desktopEnabled}
+                    label="Chatnachrichten"
+                    description="Neue Direkt- und Teamnachrichten als Windows-Push."
+                  />
+
+                  <Switch
+                    checked={settings.pushChannelMessages}
+                    onChange={(event) =>
+                      updateSetting('pushChannelMessages', event.target.checked)
+                    }
+                    disabled={!pushSupported || !settings.desktopEnabled}
+                    label="Channel-Nachrichten"
+                    description="Neue Meldungen aus Channels als Windows-Push."
+                  />
+                </div>
+
+                <p className="mt-3 text-xs text-gray-500 dark:text-gray-400">
+                  Push wird nur gesendet, wenn der jeweilige Nachrichtentyp
+                  unter „Ereignisse" ebenfalls aktiviert ist.
+                </p>
+              </div>
             </NotificationCard>
           </div>
         </Section>

frontend/src/pages/settings/presence/PresenceSettings.tsx

@@ -66,7 +66,7 @@ export default function PresenceSettings({
         onUserUpdated?.(data.user)
       }
       showToast({
-        title: 'Datenschutz gespeichert',
+        title: 'Einstellungen gespeichert',
         message: 'Deine Datenschutz- und Inaktivitätseinstellungen wurden aktualisiert.',
         variant: 'success',
       })
@@ -142,7 +142,7 @@ export default function PresenceSettings({
           </div>
 
           <Button type="submit" isLoading={saving}>
-            Datenschutz speichern
+            Speichern
           </Button>
         </form>
       </div>

frontend/src/utils/pushNotifications.ts

@@ -0,0 +1,213 @@
+const API_URL = import.meta.env.VITE_API_URL ?? 'http://localhost:8080'
+
+function absoluteAPIBaseURL() {
+  return new URL(API_URL, window.location.origin).toString().replace(/\/$/, '')
+}
+
+type PushConfig = {
+  enabled: boolean
+  publicKey: string
+}
+
+function urlBase64ToUint8Array(value: string) {
+  const padding = '='.repeat((4 - (value.length % 4)) % 4)
+  const base64 = (value + padding).replace(/-/g, '+').replace(/_/g, '/')
+  const decoded = window.atob(base64)
+
+  return Uint8Array.from(decoded, (character) => character.charCodeAt(0))
+}
+
+function arrayBuffersEqual(
+  first: ArrayBuffer | null,
+  second: Uint8Array<ArrayBuffer>,
+) {
+  if (!first || first.byteLength !== second.byteLength) {
+    return false
+  }
+
+  const firstBytes = new Uint8Array(first)
+  return firstBytes.every((value, index) => value === second[index])
+}
+
+async function readApiError(response: Response, fallback: string) {
+  const data = await response.json().catch(() => null)
+  return data?.error ?? fallback
+}
+
+async function loadPushConfig() {
+  const response = await fetch(`${API_URL}/push/config`, {
+    credentials: 'include',
+  })
+  if (!response.ok) {
+    throw new Error(
+      await readApiError(
+        response,
+        'Push-Konfiguration konnte nicht geladen werden.',
+      ),
+    )
+  }
+
+  return (await response.json()) as PushConfig
+}
+
+async function saveSubscription(subscription: PushSubscription) {
+  const serialized = subscription.toJSON()
+  const response = await fetch(`${API_URL}/push/subscriptions`, {
+    method: 'POST',
+    credentials: 'include',
+    headers: { 'Content-Type': 'application/json' },
+    body: JSON.stringify({
+      endpoint: serialized.endpoint,
+      keys: serialized.keys,
+      apiBaseUrl: absoluteAPIBaseURL(),
+    }),
+  })
+
+  if (!response.ok) {
+    throw new Error(
+      await readApiError(
+        response,
+        'Push-Abonnement konnte nicht gespeichert werden.',
+      ),
+    )
+  }
+}
+
+export function isPushNotificationSupported() {
+  return (
+    window.isSecureContext &&
+    'serviceWorker' in navigator &&
+    'PushManager' in window &&
+    'Notification' in window
+  )
+}
+
+export async function registerServiceWorker() {
+  if (!('serviceWorker' in navigator)) {
+    return null
+  }
+
+  return navigator.serviceWorker.register('/sw.js', { scope: '/' })
+}
+
+export async function syncExistingPushSubscription() {
+  if (!isPushNotificationSupported()) {
+    return false
+  }
+
+  const registration = await registerServiceWorker()
+  const subscription = await registration?.pushManager.getSubscription()
+  if (!subscription) {
+    return false
+  }
+
+  const config = await loadPushConfig()
+  if (!config.enabled || !config.publicKey) {
+    return false
+  }
+
+  const applicationServerKey = urlBase64ToUint8Array(config.publicKey)
+  if (
+    !arrayBuffersEqual(
+      subscription.options.applicationServerKey,
+      applicationServerKey,
+    )
+  ) {
+    await subscription.unsubscribe()
+    return false
+  }
+
+  await saveSubscription(subscription)
+  return true
+}
+
+export async function enablePushNotifications() {
+  if (!isPushNotificationSupported()) {
+    throw new Error(
+      'Hintergrundbenachrichtigungen benötigen HTTPS oder localhost und einen unterstützten Browser.',
+    )
+  }
+
+  const permission = await Notification.requestPermission()
+  if (permission !== 'granted') {
+    throw new Error('Windows-Benachrichtigungen wurden nicht freigegeben.')
+  }
+
+  const config = await loadPushConfig()
+  if (!config.enabled || !config.publicKey) {
+    throw new Error('Web Push ist auf dem Server noch nicht konfiguriert.')
+  }
+
+  const registration = await registerServiceWorker()
+  if (!registration) {
+    throw new Error('Der Service Worker konnte nicht registriert werden.')
+  }
+
+  const applicationServerKey = urlBase64ToUint8Array(config.publicKey)
+  let subscription = await registration.pushManager.getSubscription()
+
+  if (
+    subscription &&
+    !arrayBuffersEqual(
+      subscription.options.applicationServerKey,
+      applicationServerKey,
+    )
+  ) {
+    await subscription.unsubscribe()
+    subscription = null
+  }
+
+  subscription ??= await registration.pushManager.subscribe({
+    userVisibleOnly: true,
+    applicationServerKey,
+  })
+
+  try {
+    await saveSubscription(subscription)
+  } catch (error) {
+    await subscription.unsubscribe()
+    throw error
+  }
+
+  await registration
+    .showNotification('TEG-Benachrichtigungen aktiviert', {
+      body: 'Neue Chat- und Channel-Nachrichten werden auch im Hintergrund angezeigt.',
+      icon: '/favicon.svg',
+      badge: '/favicon.svg',
+      tag: 'teg-push-enabled',
+    })
+    .catch(() => undefined)
+
+  return true
+}
+
+export async function disablePushNotifications() {
+  if (!('serviceWorker' in navigator)) {
+    return false
+  }
+
+  const registration = await navigator.serviceWorker.getRegistration('/')
+  const subscription = await registration?.pushManager.getSubscription()
+  if (!subscription) {
+    return false
+  }
+
+  const response = await fetch(`${API_URL}/push/subscriptions`, {
+    method: 'DELETE',
+    credentials: 'include',
+    headers: { 'Content-Type': 'application/json' },
+    body: JSON.stringify({ endpoint: subscription.endpoint }),
+  })
+
+  if (!response.ok) {
+    throw new Error(
+      await readApiError(
+        response,
+        'Push-Abonnement konnte nicht entfernt werden.',
+      ),
+    )
+  }
+
+  await subscription.unsubscribe()
+  return false
+}

frontend/src/utils/titleNotifier.ts

@@ -0,0 +1,79 @@
+// Lässt den Browser-Tab-Titel blinken, solange neue Nachrichten ungelesen sind
+// und der Tab im Hintergrund liegt. Sobald der Tab wieder sichtbar wird oder
+// den Fokus erhält, wird der ursprüngliche Titel wiederhergestellt.
+
+const BLINK_INTERVAL_MS = 1000
+
+let blinkTimer: number | undefined
+let baseTitle = typeof document !== 'undefined' ? document.title : ''
+let unreadCount = 0
+let active = false
+let showingAlert = false
+
+function alertTitle() {
+  const label = unreadCount === 1 ? 'Neue Nachricht' : 'Neue Nachrichten'
+  return `(${unreadCount}) ${label}`
+}
+
+function render(showAlert: boolean) {
+  showingAlert = showAlert
+  document.title = showAlert ? alertTitle() : baseTitle
+}
+
+/**
+ * Meldet eine neue Nachricht. Startet (bzw. verlängert) das Blinken nur, wenn
+ * der Tab gerade nicht sichtbar ist – ist der Nutzer im Tab, gibt es nichts zu
+ * signalisieren.
+ */
+export function notifyNewMessage() {
+  if (typeof document === 'undefined') {
+    return
+  }
+  if (document.visibilityState === 'visible') {
+    return
+  }
+
+  if (!active) {
+    baseTitle = document.title
+    unreadCount = 0
+    active = true
+  }
+
+  unreadCount += 1
+
+  if (blinkTimer === undefined) {
+    render(true)
+    blinkTimer = window.setInterval(() => {
+      render(!showingAlert)
+    }, BLINK_INTERVAL_MS)
+  } else {
+    render(true)
+  }
+}
+
+/** Stoppt das Blinken und stellt den ursprünglichen Titel wieder her. */
+export function clearMessageNotification() {
+  if (!active) {
+    return
+  }
+
+  active = false
+  unreadCount = 0
+  showingAlert = false
+
+  if (blinkTimer !== undefined) {
+    window.clearInterval(blinkTimer)
+    blinkTimer = undefined
+  }
+
+  document.title = baseTitle
+}
+
+if (typeof window !== 'undefined' && typeof document !== 'undefined') {
+  document.addEventListener('visibilitychange', () => {
+    if (document.visibilityState === 'visible') {
+      clearMessageNotification()
+    }
+  })
+  window.addEventListener('focus', clearMessageNotification)
+}

frontend/vite.config.ts

@@ -1,11 +1,31 @@
+import { readFileSync } from 'node:fs'
+import { fileURLToPath } from 'node:url'
 import { defineConfig } from 'vite'
 import react from '@vitejs/plugin-react'
 import tailwindcss from '@tailwindcss/vite'
 
+const certDir = fileURLToPath(new URL('./certs/', import.meta.url))
+
 // https://vite.dev/config/
 export default defineConfig({
   plugins: [
     react(),
     tailwindcss(),
   ],
+  server: {
+    host: true,
+    strictPort: true,
+    https: {
+      cert: readFileSync(`${certDir}localhost.pem`),
+      key: readFileSync(`${certDir}localhost-key.pem`),
+    },
+    proxy: {
+      '/api': {
+        target: 'http://localhost:8080',
+        changeOrigin: true,
+        ws: true,
+        rewrite: (path) => path.replace(/^\/api/, ''),
+      },
+    },
+  },
 })