- Add id3 and metaflac crates for native audio tagging
- Create tagger.rs with separate tag_mp3() and tag_flac() functions
- Implement tag_audio_file Tauri command for unified tagging interface
- Support full metadata: title, artist, album, track#, ISRC, BPM, lyrics, cover art
- Create TypeScript wrapper (tagger.ts) for calling Rust backend
- Update downloader.ts to use Rust tagging for both MP3 and FLAC
- Remove browser-id3-writer dependency (no browser FLAC support)
- Inline lyrics parsing in addToQueue.ts (no longer needed in tagger)
