New read-only scan (GET /api/library/cleanup/scan) across movies, episodes,
tracks, subtitles, HLS output, transcode queue, and watchlist/progress rows:
- Missing files: DB record exists but the file is gone from disk
- Orphaned episodes: show_id no longer exists
- Orphaned HLS output: transcoded folders left behind by deleted content
- Stuck transcode jobs: "running" 2+ hours with no completion (backend-restart artifact)
- Duplicate imports: same file imported into the library more than once
- Orphaned subtitles / dangling watchlist+progress rows
Nothing is deleted until an admin clicks Fix (per-item or Fix All per
category) via POST /api/library/cleanup/fix.
Myron Blair