write_song_metadata dispatched zip-form packages on `suffix == ".sloppak"`
only, while core reads both suffixes everywhere else (sloppak.SONG_EXTS,
.feedpak being the current write extension). Editing a zip-form .feedpak's
title/artist/album/year therefore silently fell back to a DB-only update,
which looked fine until the next full library rescan re-derived metadata
from the file and reverted the edit — the exact failure this module exists
to prevent. Directory-form packages were unaffected (manifest-presence
dispatch, not suffix).
Gate on SONG_EXTS, add TestWriteSongMetadata regression coverage (both zip
suffixes, mixed-case suffix, directory form, unknown-suffix fallback), and
correct the stale scan_worker comment claiming .sloppak-suffix-only
detection (the code already accepts both via is_sloppak).
Claude-Session: https://claude.ai/code/session_01H1ZBEcZoJinde9ms5fAjwc
Co-authored-by: Claude Fable 5 <noreply@anthropic.com>
