- Add SubscriptionEntity, FeedItemEntity, SearchHistoryEntity
- Create SubscriptionDao, FeedItemDao, SearchHistoryDao with CRUD operations
- Implement RssDatabase with FTS5 virtual table for full-text search
- Add type converters for Date, String lists, and FeedItem lists
- Implement cascade delete for feed items when subscription is removed
- Add comprehensive unit tests for all DAOs
- Add database integration tests for entity round-trips and FTS
- Configure Room testing dependencies
- Add FeedItem, Feed, FeedSubscription models with Moshi JSON support
- Add SearchResult, SearchFilters models with sealed classes for enums
- Add NotificationPreferences, ReadingPreferences models
- Add Room Entity annotations for database readiness
- Add TypeConverters for Date and List<String> serialization
- Add Parcelize for passing models between Activities/Fragments
- Write comprehensive unit tests for serialization/deserialization
- Write tests for copy(), equals/hashCode, and toString functionality
