feat(app): add manual entry and sharing flows

lib/presentation/providers/ad_provider.dart

@@ -0,0 +1,7 @@
+import 'package:flutter_riverpod/flutter_riverpod.dart';
+import 'package:lunchpick/core/services/ad_service.dart';
+
+/// 광고 서비스 Provider
+final adServiceProvider = Provider<AdService>((ref) {
+  return AdService();
+});