feat(#14): finalisation redirection et nettoyage

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

frontend/lib/screens/administrateurs/admin_dashboardScreen.dart

@@ -15,13 +15,8 @@ class AdminDashboardScreen extends StatefulWidget {
 }
 
 class _AdminDashboardScreenState extends State<AdminDashboardScreen> {
-  /// null = chargement du statut setup, true/false = connu
   bool? _setupCompleted;
-
-  /// 0 = Gestion des utilisateurs, 1 = Paramètres
   int mainTabIndex = 0;
-
-  /// Sous-onglet quand mainTabIndex == 0 : 0=Gestionnaires, 1=Parents, 2=AM, 3=Administrateurs
   int subIndex = 0;
 
   @override
@@ -38,8 +33,11 @@ class _AdminDashboardScreenState extends State<AdminDashboardScreen> {
         _setupCompleted = completed;
         if (!completed) mainTabIndex = 1;
       });
-    } catch (_) {
-      if (mounted) setState(() => _setupCompleted = true);
+    } catch (e) {
+      if (mounted) setState(() {
+        _setupCompleted = false;
+        mainTabIndex = 1;
+      });
     }
   }
 
@@ -96,9 +94,7 @@ class _AdminDashboardScreenState extends State<AdminDashboardScreen> {
 
   Widget _getBody() {
     if (mainTabIndex == 1) {
-      return ParametresPanel(
-        onSetupCompleted: () => setState(() => _setupCompleted = true),
-      );
+      return ParametresPanel(redirectToLoginAfterSave: !_setupCompleted!);
     }
     switch (subIndex) {
       case 0: