fix: same-titled albums of two release groups are two albums, and a missing track with no disc is on disc 1

The scanner found an album by artist and title alone, so Weezer's six
self-titled albums (1994–2026) were one 118-track row and their merges,
wants and upgrades counted them as one. A same-named row whose release group
is known and differs from the file's is now another album; tagReadVersion 7
re-reads the library so existing tracks move to their own rows.

WantHoldings compared discs with IS NOT DISTINCT FROM, so a missing track 6
with no disc was never covered by a present disc 1 track 6. Air's Love 2
stayed wanted and was downloaded again for nothing.

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

internal/db/queries/albums.sql

@@ -36,8 +36,17 @@ WHERE albums.artist_id = $1
 ORDER BY release_date NULLS LAST, sort_title;
 
 -- name: GetAlbumByArtistAndTitle :one
--- Scanner uses this for the no-mbid dedupe path: resolve-or-create.
-SELECT * FROM albums WHERE artist_id = $1 AND title = $2 LIMIT 1;
+-- Scanner uses this for the no-mbid dedupe path: resolve-or-create. An album
+-- of the same name in another release group is a different album (Weezer's
+-- six self-titled albums shared one row until 2026-10-20), so a row whose
+-- group is known and differs is not returned. A row of the file's own group
+-- comes first, then one with no group yet.
+SELECT * FROM albums
+ WHERE artist_id = sqlc.arg(artist_id) AND title = sqlc.arg(title)
+   AND (sqlc.narg(release_group_mbid)::text IS NULL OR release_group_mbid IS NULL
+        OR release_group_mbid = sqlc.narg(release_group_mbid))
+ ORDER BY (release_group_mbid IS NOT DISTINCT FROM sqlc.narg(release_group_mbid)) DESC, id
+ LIMIT 1;
 
 -- name: ListAlbumsByArtist :many
 SELECT * FROM albums WHERE artist_id = $1 ORDER BY release_date NULLS LAST, sort_title;