#658 release: Apify-first Spotify play counts (test → main)

Promotes exactly one change: #657 — GET /api/research/track/stats serves Spotify from the song_measurements store (24h TTL, whole-album actor refresh, Songstats fallback, data_source provenance per docs#238).

Verified twice on previews (results tables on #657), including live actor run + store-fresh repeat read. Release scope checked: 8b209dad is the only commit on test not on main.

Part of recoupable/chat#1791.

🤖 Generated with Claude Code

---

Summary by cubic

Serve Spotify play counts in GET /api/research/track/stats from the song_measurements store with a 24h TTL, refreshing via the beatanalytics~spotify-play-count-scraper actor per album and writing sibling tracks. Falls back to Songstats when the store can't answer and adds data_source to every stat.

• New Features
  • For spotify + isrc: serve fresh store data; if stale, refresh album via actor and degrade to the stale value on actor failure.
  • Whole-album refresh writes all mapped tracks, with raw_ref set to the actor run id.
  • Non-Spotify or non-ISRC requests use Songstats; mixed-source queries merge store-backed Spotify with Songstats stats, labeling Songstats entries.
  • Charge 5 credits when the response is store-only; TTL is configurable via SPOTIFY_PLAYCOUNT_TTL_HOURS (default 24h).

Summary by CodeRabbit

Release Notes

• New Features
  • Integrated Apify-based Spotify playcount fetching with smart measurement caching and freshness detection
  • Implemented credit deduction system for research API requests
  • Added data source attribution to track statistics results for improved transparency