feat(frontend): simulate authenticated user sessions

eme-frontend/lib/screens/home_screen.dart

@@ -1,6 +1,7 @@
 import "package:flutter/material.dart";
 import "package:google_fonts/google_fonts.dart";
 import "../demo_identity.dart";
+import "../services/auth_service.dart";
 import "../theme/ensup_colors.dart";
 import "../widgets/ensup_top_bar.dart";
 import "../widgets/profile_card.dart";
@@ -13,6 +14,11 @@ import "restitution_select_screen.dart";
 class HomeScreen extends StatelessWidget {
   const HomeScreen({super.key});
 
+  void _quitter(BuildContext context) {
+    AuthService.clearSession();
+    Navigator.of(context).pop();
+  }
+
   @override
   Widget build(BuildContext context) {
     return Scaffold(
@@ -42,7 +48,7 @@ class HomeScreen extends StatelessWidget {
                       campusTag: DemoIdentity.campusTag,
                       userName: DemoIdentity.userName,
                       userInitials: DemoIdentity.userInitials,
-                      onBack: () => Navigator.of(context).pop(),
+                      onBack: () => _quitter(context),
                     ),
                     Expanded(
                       child: SingleChildScrollView(

eme-frontend/lib/screens/login_screen.dart

@@ -1,6 +1,7 @@
 import "package:flutter/material.dart";
 import "package:google_fonts/google_fonts.dart";
 import "../demo_identity.dart";
+import "../services/auth_service.dart";
 import "../theme/ensup_colors.dart";
 import "../widgets/ensup_top_bar.dart";
 import "../widgets/identification_option.dart";
@@ -13,6 +14,7 @@ class LoginScreen extends StatelessWidget {
   const LoginScreen({super.key});
 
   void _identifier(BuildContext context) {
+    AuthService.selectDemoStudent();
     Navigator.of(context).push(
       MaterialPageRoute(
         builder: (_) => const HomeScreen(),
@@ -21,6 +23,16 @@ class LoginScreen extends StatelessWidget {
     );
   }
 
+  void _identifierResponsable(BuildContext context) {
+    AuthService.selectDemoResponsable();
+    Navigator.of(context).push(
+      MaterialPageRoute(
+        builder: (_) => const ResponsableScreen(),
+        settings: const RouteSettings(name: "responsable"),
+      ),
+    );
+  }
+
   @override
   Widget build(BuildContext context) {
     return Scaffold(
@@ -162,15 +174,7 @@ class LoginScreen extends StatelessWidget {
                                     width: double.infinity,
                                     child: OutlinedButton.icon(
                                       onPressed: () =>
-                                          Navigator.of(context).push(
-                                            MaterialPageRoute(
-                                              builder: (_) =>
-                                                  const ResponsableScreen(),
-                                              settings: const RouteSettings(
-                                                name: "responsable",
-                                              ),
-                                            ),
-                                          ),
+                                          _identifierResponsable(context),
                                       icon: const Icon(
                                         Icons.person_outline,
                                         size: 16,

eme-frontend/lib/screens/responsable_screen.dart

@@ -2,6 +2,7 @@ import "package:flutter/material.dart";
 import "package:google_fonts/google_fonts.dart";
 
 import "../demo_identity.dart";
+import "../services/auth_service.dart";
 import "../services/responsable_service.dart";
 import "../theme/ensup_colors.dart";
 import "../utils/file_download.dart";
@@ -44,6 +45,11 @@ class _ResponsableScreenState extends State<ResponsableScreen> {
     setState(() => _future = _charger());
   }
 
+  void _quitter() {
+    AuthService.clearSession();
+    Navigator.of(context).pop();
+  }
+
   Future<void> _changerStatut(Map<String, dynamic> anomalie) async {
     final prochain = _prochainStatut(anomalie["statut"] as String?);
     if (prochain == null || _transitionEnCours) {
@@ -124,10 +130,7 @@ class _ResponsableScreenState extends State<ResponsableScreen> {
       body: SafeArea(
         child: Column(
           children: [
-            _ResponsableTopBar(
-              onExit: () => Navigator.of(context).pop(),
-              onRefresh: _rafraichir,
-            ),
+            _ResponsableTopBar(onExit: _quitter, onRefresh: _rafraichir),
             Expanded(
               child: FutureBuilder<_ResponsableData>(
                 future: _future,
@@ -249,7 +252,7 @@ class _ResponsableScreenState extends State<ResponsableScreen> {
                 anomaliesActives: anomaliesActives,
                 notificationsNonLues: notificationsNonLues,
                 onChanged: (index) => setState(() => _onglet = index),
-                onExit: () => Navigator.of(context).pop(),
+                onExit: _quitter,
               ),
             Expanded(
               child: Column(