Phase 2 of #871: clean up the duplicate videos already in the library (the #859
"same video from multiple sources" clutter). Import-time dedup (Phase 1) only
prevents NEW dups; this is the operator-triggered cleanup of existing ones.
cleanup_service.dedup_videos(dry_run):
- backfill_video_durations: re-probe NULL-duration videos (pre-#871 rows) so the
existing library participates; idempotent (only NULL rows), writes a negative
sentinel for un-probeable files so they're neither re-probed forever nor matched.
- find_video_dup_groups: cluster same-artist videos by duration (±tol) + aspect,
anchored per cluster to bound the span (no chain drift); keeper = highest pixel
area then bytes. Reuses the importer's _VIDEO_DUP_* tolerances.
- apply: re-point each loser's post links to the keeper (so no post loses the
video) THEN delete the redundant records + files via delete_images (cascade).
dry_run shares the same discovery predicate and returns the projection only
(rule 93). Tags on a loser are NOT merged (noted; videos rarely hand-curated).
- dedup_videos_task (maintenance queue; summary → task_run.metadata).
- POST /maintenance/dedup-videos {dry_run} + GET /maintenance/task-result/<id> so
the card shows the dry-run projection before the destructive apply.
- VideoDedupCard: Preview → shows groups/redundant/reclaimable, then Apply behind
a confirm dialog. Mounted in the Maintenance panel.
Tests: dedup collapses + re-links the loser's post to the keeper + removes the
file; dry-run deletes nothing; distinct durations aren't grouped; task registered.
(Migration 0052 for duration_seconds already shipped with Phase 1.)
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>