feat: integrate unified payment and wallet refunds

apps/user_app/lib/data/repositories/client_repository.dart

@@ -79,6 +79,44 @@ class ClientRepository {
     subtitleKeys: const ['amount', 'direction'],
   );
 
+  Future<List<ClientRecord>> refunds() => _records(
+    '$root/refunds',
+    titleKeys: const ['refund_no'],
+    subtitleKeys: const ['reason', 'amount'],
+    statusKey: 'refund_status',
+  );
+
+  Future<Map<String, Object?>> payOrder({
+    required String business,
+    required String identity,
+    required String requestNo,
+    required String channel,
+    required String payType,
+    String openid = '',
+  }) async => jsonMap(await _api.post(
+    '$root/$business/orders/$identity/pay',
+    body: {
+      'request_no': requestNo,
+      'channel': channel,
+        'pay_type': payType,
+        if (openid.isNotEmpty) 'openid': openid,
+    },
+  ));
+
+  Future<void> createRefund({
+    required String business,
+    required String identity,
+    required String requestNo,
+    required String reason,
+    required List<Map<String, Object?>> items,
+  }) async {
+    await _api.post('$root/$business/orders/$identity/refunds', body: {
+      'request_no': requestNo,
+      'reason': reason,
+      'items': items,
+    });
+  }
+
   Future<Map<String, Object?>?> serviceRelation() async {
     final value = await _api.get('$root/service-relation');
     if (value == null || value == '') return null;