feat(core): refonte architecture transverse (cache, network, websocket, DI)

- lib/app : app.dart, router mis à jour (routes nouveaux modules)
- lib/core/cache : cache_service + cached_datasource_decorator
- lib/core/network : api_client, offline_manager, retry_policy
- lib/core/websocket : websocket service (reconnexion exponentielle, heartbeat)
- lib/core/di : injection + register_module
- lib/core/storage : pending_operations_store (offline support)
- lib/core/navigation : main_navigation_layout (onglets par rôle)
- lib/core/config : environment, lcb_ft_constants
- lib/core/utils : error_formatter, validators
- pubspec.yaml/lock : dépendances mises à jour

lib/app/app.dart

@@ -46,7 +46,13 @@ class UnionFlowApp extends StatelessWidget {
       ],
       child: Consumer2<LocaleProvider, ThemeProvider>(
         builder: (context, locale, theme, child) {
-          return MaterialApp(
+          return BlocListener<AuthBloc, AuthState>(
+            listenWhen: (prev, curr) =>
+                curr is AuthAuthenticated && prev is! AuthAuthenticated,
+            listener: (context, _) {
+              context.read<OrgSwitcherBloc>().add(const OrgSwitcherLoadRequested());
+            },
+            child: MaterialApp(
             title: 'UnionFlow',
             debugShowCheckedModeBanner: false,
             scaffoldMessengerKey: UnionFlowApp.scaffoldMessengerKey,
@@ -79,7 +85,8 @@ class UnionFlowApp extends StatelessWidget {
                 child: child ?? const SizedBox(),
               );
             },
-          );
+          ),
+        );
         },
       ),
     );