Every Nth autoplay pick (configurable via discover_ratio), query Last.fm
for similar tracks. When Last.fm has no key or returns nothing, fall back
to MusicBrainz tag-based recording search (no API key needed). Discovered
tracks are resolved via yt-dlp and deduplicated within the session. If
discovery fails, the kept-deck shuffle continues as before.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
