similarSongsFor still filters by genre (unchanged, and getSonicSimilarTracks
remains the pure-sonic endpoint), but when the seed song has been
analyzed, genre-matched candidates that also have stored audio_features
are now ordered by actual feature-space distance from the seed instead
of SQL's random order; candidates without analysis data are left at
the end in their existing relative order rather than dropped or given
a fabricated distance.
Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_014r98AtcBbevpscWLsfwVvv
