Refactorings:
- Extract HTMLImageEmbedder and HTMLImageExtractor utilities
- Create UseCases for cached data access (GetCachedBookmarksUseCase, GetCachedArticleUseCase)
- Create CreateAnnotationUseCase to remove API dependency from ViewModel
- Simplify CachedAsyncImage by extracting helper methods
- Fix Kingfisher API compatibility (Source types, Result handling)
- Add documentation to OfflineCacheSyncUseCase
- Remove unused TestView from production code
Enforces Clean Architecture:
- ViewModels now only use UseCases, no direct Repository or API access
- All data layer access goes through Domain layer
Major improvements to offline reading functionality:
**Hero Image Offline Support:**
- Add heroImageURL field to BookmarkEntity for persistent storage
- Implement ImageCache-based caching with custom keys (bookmark-{id}-hero)
- Update CachedAsyncImage to support offline loading via cache keys
- Hero images now work offline without URL dependency
**Offline Bookmark Loading:**
- Add proactive offline detection before API calls
- Implement automatic fallback to cached bookmarks when offline
- Fix network status initialization race condition
- Network monitor now checks status synchronously on init
**Core Data Enhancements:**
- Persist hero image URLs in BookmarkEntity.heroImageURL
- Reconstruct ImageResource from cached URLs on offline load
- Add extensive logging for debugging persistence issues
**UI Updates:**
- Update BookmarkDetailView2 to use cache keys for hero images
- Update BookmarkCardView (all 3 layouts) with cache key support
- Improve BookmarksView offline state handling with task-based loading
- Add 50ms delay for network status propagation
**Technical Details:**
- NetworkMonitorRepository: Fix initial status from hardcoded true to actual network check
- BookmarksViewModel: Inject AppSettings for offline detection
- OfflineCacheRepository: Add verification logging for save/load operations
- BookmarkEntityMapper: Sync heroImageURL on save, restore on load
This enables full offline reading with hero images visible in bookmark lists
and detail views, even after app restart.
