fix: improve server connection handling during authentication

- Updated AuthStateManager to clear the active server ID upon logout, ensuring a proper return to the server connection page.
- Enhanced RouterNotifier to allow users to stay on the server connection page if authenticated, improving navigation flow.
- Modified AuthenticationPage to navigate back to the server connection page instead of popping the navigation stack, enhancing user experience during server setup.

lib/core/auth/auth_state_manager.dart

@@ -562,6 +562,10 @@ class AuthStateManager extends _$AuthStateManager {
       await storage.clearAuthData();
       _updateApiServiceToken(null);
 
+      // Clear active server to force return to server connection page
+      await storage.setActiveServerId(null);
+      ref.invalidate(activeServerProvider);
+
       // Update state
       _update(
         (current) => current.copyWith(
@@ -577,6 +581,10 @@ class AuthStateManager extends _$AuthStateManager {
     } catch (e) {
       DebugLogger.error('logout-failed', scope: 'auth/state', error: e);
       // Even if logout fails, clear local state
+      final storage = ref.read(optimizedStorageServiceProvider);
+      await storage.setActiveServerId(null);
+      ref.invalidate(activeServerProvider);
+
       _update(
         (current) => current.copyWith(
           status: AuthStatus.unauthenticated,

lib/core/router/app_router.dart

@@ -87,10 +87,13 @@ class RouterNotifier extends ChangeNotifier {
     final authState = ref.read(authNavigationStateProvider);
     final connectivityService = ref.read(connectivityServiceProvider);
 
+    // Allow staying on server connection page
     if (location == Routes.serverConnection) {
+      // If authenticated but on server connection page, go to chat
+      // Otherwise stay on server connection page (for back navigation)
       return authState == AuthNavigationState.authenticated
           ? Routes.chat
-          : Routes.authentication;
+          : null;
     }
 
     // Check connectivity status to determine if we should show connection issue

lib/features/auth/views/authentication_page.dart

@@ -205,7 +205,7 @@ class _AuthenticationPageState extends ConsumerState<AuthenticationPage> {
       children: [
         ConduitIconButton(
           icon: Platform.isIOS ? CupertinoIcons.back : Icons.arrow_back,
-          onPressed: () => Navigator.pop(context),
+          onPressed: () => context.go(Routes.serverConnection),
           tooltip: AppLocalizations.of(context)!.backToServerSetup,
         ),
         const Spacer(),