fix: ensure notifications use correct channels and dates

lib/controllers/add_subscription_controller.dart

@@ -9,7 +9,6 @@ import '../services/subscription_url_matcher.dart';
 import '../widgets/common/snackbar/app_snackbar.dart';
 import '../l10n/app_localizations.dart';
 import '../utils/billing_date_util.dart';
-import '../utils/business_day_util.dart';
 import 'package:permission_handler/permission_handler.dart' as permission;
 
 /// AddSubscriptionScreen의 비즈니스 로직을 관리하는 Controller
@@ -495,7 +494,6 @@ class AddSubscriptionController {
         );
         var adjustedNext =
             BillingDateUtil.ensureFutureDate(originalDateOnly, billingCycle);
-        adjustedNext = BusinessDayUtil.nextBusinessDay(adjustedNext);
 
         await Provider.of<SubscriptionProvider>(context, listen: false)
             .addSubscription(