Merge develop into master (squash)

- Ticket #92: endpoint GET /gestionnaires, dashboard admin données réelles
- Seed données de test, script reset-and-seed-db.sh
- Modèles frontend (Parent, AM), user_service, widgets admin

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'));
     }