both lanes now expose the post-processing phase instead of jumping downloading→completed:
- YouTube now STAGES in the shared download folder (a 'youtube' subdir) then transfers to
the library — same as movies/TV — so no partial .part files land in the Plex folder.
process_youtube_download gains stage_dir + move seams: download → 'importing' → move →
completed (import_failed if the move dies; wish kept for retry). falls back to
straight-to-library when no download folder is set.
- movies/TV: the organizer flips the row to 'importing' before the (slow) move + sidecars +
subtitles, so that phase is visible.
- 'importing' is now an active status (get_active_video_downloads + youtube concurrency count
+ the downloads page status map), so the row stays on the page + holds its worker slot.
tested (staging + import-failure paths).