added batch file upload logic

lib/screens/groups/controllers/group_controller.dart

@@ -2,6 +2,7 @@ import 'package:flutter/material.dart';
 import 'package:qpay/http/http.dart';
 import 'package:qpay/models/api_response.dart';
 import 'package:qpay/models/pageable_model.dart';
+import 'package:qpay/screens/groups/models/create_group_from_file_response.dart';
 import 'package:qpay/screens/groups/models/recipient_group_model.dart';
 
 class GroupScreenModel {
@@ -80,8 +81,9 @@ class GroupController extends ChangeNotifier {
         '/public/recipient-groups?${buildQueryParameters(params)}',
       );
       final response = _unwrap(raw);
-      final pageableModel =
-          PageableModel.fromJson(response as Map<String, dynamic>);
+      final pageableModel = PageableModel.fromJson(
+        response as Map<String, dynamic>,
+      );
 
       final newGroups = pageableModel.content
           .map((e) => RecipientGroup.fromJson(e as Map<String, dynamic>))
@@ -113,10 +115,7 @@ class GroupController extends ChangeNotifier {
     }
   }
 
-  Future<void> searchGroups({
-    required String userId,
-    String? name,
-  }) async {
+  Future<void> searchGroups({required String userId, String? name}) async {
     model.searchQuery = name ?? '';
     await listGroups(userId: userId, page: 0, name: name);
   }
@@ -252,4 +251,50 @@ class GroupController extends ChangeNotifier {
       await deleteGroup(groupId: id, userId: userId);
     }
   }
-}
+
+  Future<ApiResponse<CreateGroupFromFileResponse>> createGroupFromFile({
+    required String groupName,
+    required String userId,
+    String? description,
+    required String currency,
+    required List<int> fileBytes,
+    required String fileName,
+  }) async {
+    model.isLoading = true;
+    if (!_disposed) notifyListeners();
+
+    try {
+      final fields = <String, String>{
+        'groupName': groupName,
+        'userId': userId,
+        'currency': currency,
+      };
+      if (description != null && description.isNotEmpty) {
+        fields['description'] = description;
+      }
+
+      final raw = await http.multipartPost(
+        '/public/recipient-groups/create-from-file',
+        fields,
+        'file',
+        fileBytes,
+        fileName,
+      );
+      final response = _unwrap(raw);
+      final result = CreateGroupFromFileResponse.fromJson(
+        response as Map<String, dynamic>,
+      );
+
+      model.isLoading = false;
+      if (!_disposed) notifyListeners();
+
+      return ApiResponse.success(result);
+    } catch (e) {
+      logger.e(e);
+      model.errorMessage = e.toString();
+      model.isLoading = false;
+      if (!_disposed) notifyListeners();
+      return ApiResponse.failure('Failed to create group from file');
+    }
+  }
+}