feat(12-01): implement library CRUD methods and orphan cleanup pipeline
- Add AddLibrary, RenameLibrary, RemoveLibrary, GetRemovalImpact methods
- RemoveLibrary follows exact order: phantom populate → delete audio_files → orphan cleanup → commit → FTS5 rebuild → cover art file cleanup → queue compact → events
- Add cancelLibraryScan and currentTrackBelongsToLibrary helpers
- Add RemovalHooks type and removalHooks field on Library struct
- Add LibraryAdded, LibraryRenamed, LibraryRemoved event constants
- Regenerate frontend events.ts with new CRUD events
- All hand-crafted SQL has SAFETY comments per project convention
- Dual artist_credit FK check (recordings + release_groups) for orphan cleanup
yonlu
bd44f8306c