feat: add role-based authentication support and update UI toggle label to Agent

lib/features/auth/data/auth_repository.dart

@@ -38,11 +38,16 @@ class AuthRepository {
   Future<Map<String, dynamic>> login({
     required String email,
     required String password,
+    String? loginRole,
   }) async {
     try {
       final response = await _dio.post(
         ApiConstants.authLogin,
-        data: {'email': email, 'password': password},
+        data: {
+          'email': email,
+          'password': password,
+          if (loginRole != null) 'loginRole': loginRole,
+        },
       );
 
       final data = response.data['data'] as Map<String, dynamic>;