HandleGetWatchDetail populated user_data (resume position) only for
movie/episode/ebook, so an audiobook fetched via /watch returned a null
position_seconds even though progress is recorded the same way. The
/catalog/items/{id} path already includes audiobooks; this brings the watch
endpoint in line so both expose the saved position.
Co-authored-by: rxwatcher <rxwatcher@users.noreply.github.com>
Co-authored-by: Claude Opus 4.8 <noreply@anthropic.com>