Multi-user sharing, groups, and in-app notifications

Backend:
- Alembic migration 0025: groups, group_memberships, project_shares,
  note_shares, notifications tables
- models: Group, GroupMembership, ProjectShare, NoteShare, Notification
- services/access.py: permission resolution (viewer/editor/admin/owner)
- services/groups.py + routes/groups.py: full group CRUD + membership
- services/sharing.py + routes/shares.py: project/note sharing API
- services/notifications.py: in-app notification create/list/mark-read
- routes/in_app_notifications.py: GET/POST notification endpoints
- routes/users.py: user search endpoint
- services/projects.py + services/notes.py: *_for_user variants
- routes updated to use *_for_user on get/list; adds permission field
- app.py: register all new blueprints

Frontend:
- api/client.ts: ShareEntry, GroupEntry, NotificationEntry types + helpers
- stores/notifications.ts: Pinia store with polling
- NotificationBell.vue: bell icon + badge + dropdown toggle + 60s poll
- NotificationsPanel.vue: unread notification list with mark-all-read
- ShareDialog.vue: teleport modal for sharing projects/notes with users/groups
- SharedWithMeView.vue: /shared route listing shared projects and notes
- AppHeader: NotificationBell, Shared nav link
- ProjectView, NoteViewerView, TaskViewerView: Share button + ShareDialog
- SettingsView: Groups admin tab with create/delete groups + member mgmt
- router: /shared route

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

src/fabledassistant/app.py

@@ -22,6 +22,10 @@ from fabledassistant.routes.push import push_bp
 from fabledassistant.routes.quick_capture import quick_capture_bp
 from fabledassistant.routes.settings import settings_bp
 from fabledassistant.routes.tasks import tasks_bp
+from fabledassistant.routes.groups import groups_bp
+from fabledassistant.routes.shares import shares_bp
+from fabledassistant.routes.in_app_notifications import notifications_bp
+from fabledassistant.routes.users import users_bp
 
 STATIC_DIR = Path(__file__).parent / "static"
 logger = logging.getLogger(__name__)
@@ -67,6 +71,10 @@ def create_app() -> Quart:
     app.register_blueprint(settings_bp)
     app.register_blueprint(task_logs_bp)
     app.register_blueprint(tasks_bp)
+    app.register_blueprint(groups_bp)
+    app.register_blueprint(shares_bp)
+    app.register_blueprint(notifications_bp)
+    app.register_blueprint(users_bp)
 
     @app.before_request
     async def before_request():