added support for 2fa login with browser flow

lib/routing/app_routes.dart

@@ -18,6 +18,7 @@ import '../state/app/modules/app_modules.dart';
 import '../state/app/modules/chat/bloc/chat_bloc.dart';
 import '../state/app/modules/chat_list/bloc/chat_list_bloc.dart';
 import '../state/app/modules/marianum_message/bloc/marianum_message_state.dart';
+import '../view/login/nextcloud_login_flow_page.dart';
 import '../view/pages/files/files.dart';
 import '../view/pages/files/sharing/sharee_picker_page.dart';
 import '../view/pages/foreign_timetable/element_picker_page.dart';
@@ -114,6 +115,20 @@ class AppRoutes {
     );
   }
 
+  /// Runs the Nextcloud Login Flow v2 (browser login, e.g. for accounts with
+  /// two-factor authentication) and resolves to `true` once an app password
+  /// was adopted. Used from the login flow and the settings "reconnect"
+  /// action.
+  static Future<bool> openNextcloudLoginFlow(BuildContext context) async {
+    final result = await Navigator.of(context).push<bool>(
+      MaterialPageRoute(
+        fullscreenDialog: true,
+        builder: (_) => const NextcloudLoginFlowPage(),
+      ),
+    );
+    return result ?? false;
+  }
+
   /// Opens the tappable, zoomable profile-picture viewer for [id].
   static void openLargeProfilePicture(BuildContext context, String id) {
     Navigator.of(context).push(