pruneEmptyEntities deleted empty albums but never the cover_art rows they referenced, so removing the last track of an album leaked the row and its files forever — the janitor's covers sweep computes its live set from cover_art.file_path, which keeps the orphaned row's files exempt. Extract sweepOrphanedCoverArt/removeCoverArtFiles as one implementation and run it from pruneEmptyEntities (scan orphan path and RemoveFromLibrary) and RemoveLibrary alike. Closes #247