feat(ui): 결제 금액 UI 표시 적용

lib/widgets/subscription_list_widget.dart

@@ -12,6 +12,7 @@ import './dialogs/delete_confirmation_dialog.dart';
 import './common/snackbar/app_snackbar.dart';
 import '../l10n/app_localizations.dart';
 import '../utils/logger.dart';
+import '../utils/billing_cost_util.dart';
 import '../utils/subscription_grouping_helper.dart';
 import 'native_ad_widget.dart';
 import 'package:google_mobile_ads/google_mobile_ads.dart';
@@ -159,12 +160,17 @@ class SubscriptionListWidget extends StatelessWidget {
     );
   }
 
-  /// 특정 통화의 총 합계를 계산합니다.
+  /// 특정 통화의 실제 결제 금액 총 합계를 계산합니다.
   double _calculateTotalByCurrency(
       List<SubscriptionModel> subscriptions, String currency) {
-    return subscriptions
-        .where((sub) => sub.currency == currency)
-        .fold(0.0, (sum, sub) => sum + sub.monthlyCost);
+    return subscriptions.where((sub) => sub.currency == currency).fold(
+        0.0,
+        (sum, sub) =>
+            sum +
+            BillingCostUtil.convertFromMonthlyCost(
+              sub.currentPrice,
+              sub.billingCycle,
+            ));
   }
 }