The audit log treats lidarr_album_mbid as a 'this row triggered Lidarr'
marker. Setting it on Resolve/DeleteFile (where Lidarr is never contacted)
muddied that semantic. Reverting to plan: only DeleteViaLidarr writes the
mbid. Adds an idempotency test for Resolve over a track with zero rows
(audit row written, affected_users=0, mbid nil).
bvandeusen
ef3fffb3ea