Discord (Shdjfgatdif): "if a track isn't imported it should remain there, not be deleted, so we
can retry." He was seeing failed downloads disappear and having to re-download.
Normally a rejected file is QUARANTINED (moved to ss_quarantine, preserved + retryable), not
deleted. But all four quarantine blocks (integrity / silence / quality / acoustid) had the same
fallback: if move_to_quarantine itself raised, os.remove(file_path). On a NAS that move can fail
(cross-device / permissions), so the except fired and the user's download was DELETED — the worst
outcome, and exactly the re-download pain he reported.
fix: on quarantine failure, log and LEAVE the file in place — never delete. The task is still
marked failed and the batch still notified (that code runs after the try/except and never touched
the deleted file), so the only behaviour change is "preserved instead of destroyed". Reviewed
every os.remove in the pipeline: the remaining ones are success-path cleanups (replacing an
existing destination, or removing a redundant download when the track is already in the library at
equal/better quality) — left untouched.
regression test drives the REAL pipeline through integrity-rejection with quarantine forced to
raise, and asserts the source file is preserved while the task is still failed + notified.
1311 imports/downloads/quality tests green, ruff clean.
8abf470018