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/models/assistante_maternelle_model.dart

@@ -0,0 +1,30 @@
+import 'package:p_tits_pas/models/user.dart';
+
+class AssistanteMaternelleModel {
+  final AppUser user;
+  final String? approvalNumber;
+  final String? residenceCity;
+  final int? maxChildren;
+  final int? placesAvailable;
+
+  AssistanteMaternelleModel({
+    required this.user,
+    this.approvalNumber,
+    this.residenceCity,
+    this.maxChildren,
+    this.placesAvailable,
+  });
+
+  factory AssistanteMaternelleModel.fromJson(Map<String, dynamic> json) {
+    final userJson = json['user'] ?? json;
+    final user = AppUser.fromJson(userJson);
+    
+    return AssistanteMaternelleModel(
+      user: user,
+      approvalNumber: json['numero_agrement'] as String?,
+      residenceCity: json['ville_residence'] as String?,
+      maxChildren: json['nb_max_enfants'] as int?,
+      placesAvailable: json['place_disponible'] as int?,
+    );
+  }
+}