feat: add payment card grouping and analysis

lib/controllers/add_subscription_controller.dart

@@ -4,6 +4,7 @@ import 'package:provider/provider.dart';
 import 'package:intl/intl.dart';
 import '../providers/subscription_provider.dart';
 import '../providers/category_provider.dart';
+import '../providers/payment_card_provider.dart';
 import '../services/sms_service.dart';
 import '../services/subscription_url_matcher.dart';
 import '../widgets/common/snackbar/app_snackbar.dart';
@@ -31,6 +32,7 @@ class AddSubscriptionController {
   DateTime? nextBillingDate;
   bool isLoading = false;
   String? selectedCategoryId;
+  String? selectedPaymentCardId;
 
   // Event State
   bool isEventActive = false;
@@ -126,6 +128,13 @@ class AddSubscriptionController {
       // Localizations가 아직 준비되지 않은 경우 기본값 유지
     }
 
+    // 기본 결제수단 설정
+    try {
+      final paymentCardProvider =
+          Provider.of<PaymentCardProvider>(context, listen: false);
+      selectedPaymentCardId = paymentCardProvider.defaultCard?.id;
+    } catch (_) {}
+
     // 애니메이션 시작
     animationController!.forward();
   }
@@ -503,6 +512,7 @@ class AddSubscriptionController {
           nextBillingDate: adjustedNext,
           websiteUrl: websiteUrlController.text.trim(),
           categoryId: selectedCategoryId,
+          paymentCardId: selectedPaymentCardId,
           currency: currency,
           isEventActive: isEventActive,
           eventStartDate: eventStartDate,