create project

frontend/lib/api/bill_api.dart

@@ -0,0 +1,18 @@
+import 'api_client.dart';
+import 'package:flutter/foundation.dart';
+
+class BillApi {
+  final ApiClient _client;
+  BillApi(this._client);
+
+  Future<Map<String, dynamic>> getBills({String? userId, String? familyId}) {
+    final params = <String, dynamic>{};
+    if (userId != null) params['userId'] = userId;
+    if (familyId != null) params['familyId'] = familyId;
+    return _client.get('/bills', params: params);
+  }
+
+  Future<Map<String, dynamic>> createBill(Map<String, dynamic> data) {
+    return _client.post('/bills', data: data);
+  }
+}