// image_repository.dart
abstract class ImageRepository {
  Future<String> downloadImage(String imageUrl, String problemId);
  Future<bool> isImageDownloaded(String imageUrl, String problemId);
  Future<String?> getLocalImagePath(String imageUrl, String problemId);
  Future<void> deleteProblemImages(String problemId);
  Future<void> cleanupCache({Duration maxAge = const Duration(days: 30)});
}