admin management 기능 추가

frontend/lib/main.dart

@@ -8,7 +8,7 @@ import 'package:google_fonts/google_fonts.dart';
 import 'package:flutter_web_plugins/url_strategy.dart';
 import 'features/auth/presentation/login_screen.dart';
 import 'features/dashboard/presentation/dashboard_screen.dart';
-import 'features/admin/presentation/create_user_screen.dart';
+import 'features/admin/presentation/user_management_screen.dart';
 import 'core/services/auth_proxy_service.dart';
 import 'core/services/logger_service.dart';
 import 'package:logging/logging.dart';
@@ -90,7 +90,7 @@ final _router = GoRouter(
       path: '/admin/users',
       builder: (context, state) {
         _routerLogger.info("Navigating to /admin/users");
-        return const CreateUserScreen();
+        return const UserManagementScreen();
       },
     ),
   ],