Two related gaps surfaced from "uploaded a track, nothing changed / no status":
- A track could stay stuck on `pending` forever (an unexpected worker error
rolled back the run without recording anything), and `failed` carried no
reason. Add `tracks.metadata_error` + `tracks.enriched_at` (migration), stamp
the outcome in apply_enrichment, add TrackRepository.mark_enrichment_failed,
wrap enrich_task to persist crashes as `failed` in a fresh session, and emit a
human-readable no-match reason. Expose metadata_error/enriched_at in TrackOut.
- The tag-first merge let junk embedded tags (e.g. "Music Track"/"Sound_13958")
override even a 0.99-confidence AcoustID match. Add acoustid_trust_score
(default 0.85): above it the acoustic identity wins for title/artist/album/
year, tags are fallback; below it, tag-first as before.
Add a license-free real-file fixture (Scarlet Fire / Otis McDonald) whose junk
tags AcoustID overrides, with an always-on tag-reader test plus fpcalc/AcoustID/
network-gated identity + full-pipeline tests (skip on host, run in the container).
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Senko-san