added support for 2fa login with browser flow

lib/view/login/widgets/login_card.dart

@@ -1,5 +1,6 @@
 import 'package:flutter/material.dart';
 
+import '../../../routing/app_routes.dart';
 import '../login_controller.dart';
 import 'login_error_banner.dart';
 
@@ -51,11 +52,27 @@ class _LoginCardState extends State<LoginCard> {
   Future<void> _submit() async {
     if (widget.controller.loading) return;
     if (!(_formKey.currentState?.validate() ?? false)) return;
-    final ok = await widget.controller.submit(
+    final result = await widget.controller.submit(
       _usernameController.text,
       _passwordController.text,
     );
-    if (ok && mounted) widget.onSuccess();
+    if (!mounted) return;
+    switch (result) {
+      case LoginResult.success:
+        widget.onSuccess();
+      case LoginResult.nextcloudLoginRequired:
+        // 2FA (oder abweichendes NC-Passwort): Anmeldung im Browser über den
+        // Login Flow v2 abschließen; ohne Erfolg wird der Login zurückgerollt.
+        final ok = await AppRoutes.openNextcloudLoginFlow(context);
+        if (!mounted) return;
+        if (ok) {
+          widget.onSuccess();
+        } else {
+          await widget.controller.abortNextcloudLogin();
+        }
+      case LoginResult.failure:
+        break;
+    }
   }
 
   InputDecoration _decoration(ThemeData theme, String label, IconData icon) =>