Local music directory matching for rabbithole player

[magent-cryptograss]

Summary

Allow users to point at their local music directory so the rabbithole player can use local files instead of streaming, saving bandwidth.

Proposed Flow

1. User grants access to music directory via File System Access API
2. Scan directory for audio files
3. Match against catalog using checksums (not just filenames)
4. Store directory handle in IndexedDB for session persistence
5. When loading a song, check for local match before streaming

Technical Notes

• Directory handles can be stored in IndexedDB, require re-verification on new sessions
• Checksum matching more reliable than filename matching
• Consider scanning time for large directories
• Storage quota considerations for any caching

Related

• Current single-file caching via IndexedDB already working
• Source indicator shows "local" vs "stream"