Search any configured source (tabs, default active) and surface the SAME song
across its collections (single/EP/album) so the user can pick which release a
track should be filed under.
- core/imports/rematch_search.py: pure normalize + injected client factory.
search_release_candidates() → lightweight display rows from typed search_tracks
(title/artist/release/type badge/year/count/art/isrc/track_id); resolve_hint_fields()
runs ONCE on the picked row via get_track_details to pull the album_id (+ isrc/
track#/disc) the hint needs. infer_release_type() handles Spotify's missing 'EP'
(multi-track 'single' → EP badge); filing is driven by real album_id, not the label.
- GET /api/reidentify/sources (tabs) + GET /api/reidentify/search (rows). Graceful
empty on dead source / blank query / client error — never raises.
14 tests. Inert until the modal (Phase 4) calls it.
