feat(dashboard-admin): connect admin dashboard to real API data (Ticket #92)

- Frontend:
  - Create UserService to handle user-related API calls (gestionnaires, parents, AMs, admins)
  - Update AdminDashboardScreen to use dynamic widgets
  - Implement dynamic management widgets:
    - GestionnaireManagementWidget
    - ParentManagementWidget
    - AssistanteMaternelleManagementWidget
    - AdminManagementWidget
  - Add data models: ParentModel, AssistanteMaternelleModel
  - Update AppUser model
  - Update ApiConfig

- Backend:
  - Update controllers (Parents, AMs, Gestionnaires, Users) to allow ADMINISTRATEUR role to list users
  - Note: Gestionnaires endpoint is currently bypassed in frontend (using /users filter) due to module import issue (documented in docs/92_NOTE-BACKEND-GESTIONNAIRES.md)

- Docs:
  - Add note about backend fix for Gestionnaires module
  - Update .cursorrules to forbid worktrees

Co-authored-by: Cursor <cursoragent@cursor.com>

frontend/lib/screens/administrateurs/admin_dashboardScreen.dart

@@ -3,6 +3,7 @@ import 'package:p_tits_pas/services/configuration_service.dart';
 import 'package:p_tits_pas/widgets/admin/assistante_maternelle_management_widget.dart';
 import 'package:p_tits_pas/widgets/admin/gestionnaire_management_widget.dart';
 import 'package:p_tits_pas/widgets/admin/parent_managmant_widget.dart';
+import 'package:p_tits_pas/widgets/admin/admin_management_widget.dart';
 import 'package:p_tits_pas/widgets/admin/parametres_panel.dart';
 import 'package:p_tits_pas/widgets/app_footer.dart';
 import 'package:p_tits_pas/widgets/admin/dashboard_admin.dart';
@@ -104,7 +105,7 @@ class _AdminDashboardScreenState extends State<AdminDashboardScreen> {
       case 2:
         return const AssistanteMaternelleManagementWidget();
       case 3:
-        return const Center(child: Text('👨‍💼 Administrateurs'));
+        return const AdminManagementWidget();
       default:
         return const Center(child: Text('Page non trouvée'));
     }