Union-find near-duplicate detection over cached CLIP image embeddings (no re-embedding) — a tunable threshold slider + Strict/Balanced/Relaxed presets, per-group average similarity via a cosine-similarity-meter, keep-first selection + bulk delete, and a cancellable scan that re-groups (never re-embeds) on threshold change. Own usePhotoLibrary instance + its own media-dropzone ingest. Split from ui/blocks/photo-search (Duplicates tab).