completed group batch feature

lib/screens/onboarding/login/login_controller.dart

@@ -1,5 +1,6 @@
 import 'package:dio/dio.dart';
 import 'package:flutter/material.dart';
+import 'package:qpay/auth_state.dart';
 import 'package:qpay/http/http.dart';
 import 'package:qpay/models/api_response.dart';
 import 'package:shared_preferences/shared_preferences.dart';
@@ -60,15 +61,22 @@ class LoginController extends ChangeNotifier {
         prefs.setString('username', username);
         prefs.setString('email', response['email']);
         prefs.setString('firstName', response['firstName']);
-        prefs.setString('lastName', response['lastName']);
+        prefs.setString('lastName', response['lastName'] ?? '');
         prefs.setString('phone', response['phone']);
         prefs.setString('userId', response['uuid']);
         prefs.setString(
           'initials',
           response['firstName'].substring(0, 1) +
-              response['lastName'].substring(0, 1),
+              (response['lastName'] != null && response['lastName'].isNotEmpty
+                  ? response['lastName'].substring(0, 1)
+                  : ''),
         );
 
+        // Notify the router that the user is now signed in so any
+        // auth-gated redirects (e.g. the groups flow) are re-evaluated
+        // and the user is sent to their originally requested page.
+        await authState.refresh();
+
         return ApiResponse.success(model);
       } else {
         model.errorMessage =