Search Improvements

Branch: feature/search-improvements

Completed

Add playlists and audiobooks to search results
- Parse from MA API response
- Filter chips for each type
- Tile builders with navigation to detail screens
Unified Relevance-Based "All" Results
- Scoring algorithm implemented:
  - Exact match: 100 points
  - Starts with query: 80 points
  - Contains query (word boundary): 60 points
  - Contains query (anywhere): 40 points
  - Fuzzy match: 20 points
  - Bonus for library items (albums): +10 points
  - Bonus for favorites: +5 points
  - Secondary field matching (artist name in albums/tracks)
- Merged all results into single sorted list
- Type indicators in subtitle (e.g., "Artist • Album")
Smart Cross-Referencing
- Extracts unique artists from matched tracks/albums
- Filters to artists whose name contains query words (min 3 chars)
- Adds cross-referenced artists with lower relevance score (25)
- Avoids duplicates with direct search results
Past Searches Row
- Added SearchHistory table to database (schema v4)
- Saves successful searches (deduplicated, max 10)
- Displays as ActionChips in empty state
- Clicking chip performs that search

Library-only toggle: Add switch to filter search to library items only (MA API supports this)
Voice search: Add microphone button if platform supports speech recognition
Search suggestions: Typeahead from library as user types
Quick actions: Long-press result for play/queue options without navigating
Clear history in settings: Add option to clear search history

File	Changes
`lib/database/database.dart`	Added SearchHistory table, schema v4
`lib/services/database_service.dart`	Added search history methods
`lib/screens/search_screen.dart`	Relevance scoring, cross-refs, history UI
`lib/l10n/app_en.arb`	Added localization strings