Root cause: the only album-context backfill in the download path (hydrate_download_metadata) goes
through spotify_client.get_track_details — Spotify-only. An iTunes/Deezer-primary user's download
kept a lean context (no release_date), so the path dropped $year and the date defaulted to
YYYY-01-01 — until they ran a Reorganize, which reads the full album from the PRIMARY source. That
asymmetry IS the bug.
Fix: when the context is lean and the primary source isn't Spotify, hydrate it from that source via
get_album_for_source — the exact path Reorganize/Enrich use. Verified the primary source returns the
real data (live iTunes get_album for the reporter's album: release_date 2024-04-17, not 2024-01-01).
backfill_album_context_from_source is a pure, injected-fn seam: 6 tests (hydrate, no-op when
complete / spotify-primary / sentinel-id, stays-lean on None, swallows source errors). 552 downloads
tests green.
2b17ed8451