fix: a second copy of a track counts once, joining words don't part two titles, and a newer matcher retries an older one's refusals (M502 #5569)

The second run's refusals were mostly albums holding a track twice (a
two-track single with three files), which no edition can pair, and
release names that differ only in "+" against "/". Tracks are now read
once per disc, number and title, and "and", "&" and "+" count for nothing
when titles are compared; an edition's own title also counts as the
album's name.

library_album_matches records which matcher version decided each album.
Refusals by an older version are matched again, even after the listing is
done, so an improvement reaches them without a migration.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

internal/db/queries/wanted.sql

@@ -272,18 +272,24 @@ SELECT a.id, 'listed', 'tags', a.release_group_mbid
 ON CONFLICT (album_id) DO NOTHING;
 
 -- name: ListAlbumsToMatch :many
--- Library albums from before the cutoff that the listing has not decided:
--- each is matched to MusicBrainz (#5569). An album row with no tracks is
--- not an album in the library.
+-- Library albums from before the cutoff that the listing has not decided,
+-- or that an older matcher refused: each is matched to MusicBrainz (#5569).
+-- An album row with no tracks is not an album in the library.
 SELECT a.id, a.title, a.mbid, a.release_group_mbid, ar.name AS artist_name, ar.mbid AS artist_mbid
   FROM albums a
   JOIN artists ar ON ar.id = a.artist_id
  WHERE a.created_at <= sqlc.arg(cutoff)::timestamptz
    AND EXISTS (SELECT 1 FROM tracks t WHERE t.album_id = a.id)
-   AND NOT EXISTS (SELECT 1 FROM library_album_matches m WHERE m.album_id = a.id)
+   AND NOT EXISTS (SELECT 1 FROM library_album_matches m
+                    WHERE m.album_id = a.id AND (m.outcome = 'listed' OR m.matcher >= sqlc.arg(matcher)::int))
  ORDER BY a.created_at, a.id
  LIMIT sqlc.arg(max_rows);
 
+-- name: CountAlbumsToRematch :one
+-- Refusals by an older matcher, which a finished listing goes back to.
+SELECT COUNT(*) FROM library_album_matches
+ WHERE outcome = 'unmatched' AND matcher < sqlc.arg(matcher)::int;
+
 -- name: ListAlbumTracksToMatch :many
 -- What an album's tracks say about themselves, to check a match against.
 SELECT title, disc_number, track_number, duration_ms, mbid
@@ -308,18 +314,20 @@ VALUES (sqlc.arg(release_group_mbid), sqlc.arg(artist_mbid), sqlc.arg(artist_nam
 ON CONFLICT (release_group_mbid) DO NOTHING;
 
 -- name: RecordAlbumMatch :exec
-INSERT INTO library_album_matches (album_id, outcome, method, release_group_mbid, detail)
-VALUES (sqlc.arg(album_id), sqlc.arg(outcome), sqlc.arg(method), sqlc.arg(release_group_mbid), sqlc.arg(detail))
+INSERT INTO library_album_matches (album_id, outcome, method, release_group_mbid, detail, matcher)
+VALUES (sqlc.arg(album_id), sqlc.arg(outcome), sqlc.arg(method), sqlc.arg(release_group_mbid), sqlc.arg(detail),
+        sqlc.arg(matcher))
 ON CONFLICT (album_id) DO UPDATE
-   SET outcome = EXCLUDED.outcome, method = EXCLUDED.method,
-       release_group_mbid = EXCLUDED.release_group_mbid, detail = EXCLUDED.detail, decided_at = now();
+   SET outcome = EXCLUDED.outcome, method = EXCLUDED.method, release_group_mbid = EXCLUDED.release_group_mbid,
+       detail = EXCLUDED.detail, matcher = EXCLUDED.matcher, decided_at = now();
 
 -- name: FinishLibraryListing :one
--- The listing is done: count the albums no match was found for.
+-- The listing is done, or done again after a newer matcher's retries:
+-- count the albums no match was found for. The first finish is kept.
 UPDATE acquisition_settings
-   SET library_listed_at = now(),
+   SET library_listed_at = COALESCE(library_listed_at, now()),
        library_unlisted = (SELECT COUNT(*) FROM library_album_matches WHERE outcome = 'unmatched')
- WHERE id = true AND library_listed_at IS NULL
+ WHERE id = true
 RETURNING library_listed_at, library_unlisted;
 
 -- name: ListUnmatchedLibraryAlbums :many