- _replaceSafFileVia: op now registers produced files via addCleanup
the moment they exist, so converted temp files are deleted even
when a later step throws (old code's outer-variable finally)
- native worker history: recompute format from the final file path
at history-write time and gate bitrate on lossy output again -
the extracted helper was recording pre-conversion format/bitrate
(FLAC conversions logged as m4a with nulled bit depth on SAF)
- drop dead ignore_for_file header in the finalization part
Pure move: paths, native worker, finalization, ReplayGain, and
metadata embedding move to part files as private extensions on
DownloadQueueNotifier; queue orchestration, state, and public API
stay in the main file (7598 -> 4022 lines).
zarzet