fix: an album with missing tracks is wanted back by its release group, not only when it carries a release MBID (#6167)

The release id was only ever used to find the group. 238 albums matched to a
group carried none, so their losses, five of the resolver's wrong-slot
removals among them, were never fetched again.

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

internal/db/dbq/reacquisition.sql.go

@@ -17,7 +17,7 @@ SELECT COUNT(DISTINCT albums.id)::bigint
   JOIN artists ON artists.id = albums.artist_id
   JOIN tracks  ON tracks.album_id = albums.id
  WHERE tracks.missing_since IS NOT NULL
-   AND (albums.mbid IS NULL OR artists.mbid IS NULL)
+   AND ((albums.mbid IS NULL AND albums.release_group_mbid IS NULL) OR artists.mbid IS NULL)
 `
 
 // Albums with missing files that can never be wanted automatically because
@@ -105,7 +105,7 @@ SELECT albums.id                 AS album_id,
   JOIN tracks  ON tracks.album_id = albums.id
  WHERE tracks.missing_since IS NOT NULL
    AND tracks.missing_since <= now() - make_interval(hours => $1::int)
-   AND albums.mbid IS NOT NULL
+   AND (albums.mbid IS NOT NULL OR albums.release_group_mbid IS NOT NULL)
    AND artists.mbid IS NOT NULL
  GROUP BY albums.id, albums.title, albums.mbid, albums.release_group_mbid,
           artists.name, artists.mbid
@@ -141,8 +141,11 @@ type ListAlbumsDueReacquisitionRow struct {
 //   - it still has at least one track whose file has been missing longer than
 //     the grace window. Measured on missing_since, which reconcile never
 //     re-stamps (#2523), so it is a genuine "gone since" clock;
-//   - MusicBrainz can name it: the album and its artist have MBIDs. Albums
-//     failing this are counted separately (CountAlbumsMissingWithoutMbid);
+//   - MusicBrainz can name it: the artist has an MBID, and the album a
+//     release MBID or a release group. The release MBID is only ever used to
+//     find the group, and 238 albums matched to a group carried no release
+//     id, so their losses were never wanted back (#6167). Albums failing this
+//     are counted separately (CountAlbumsMissingWithoutMbid);
 //   - it is on the wanted list (#5567): an album taken off the list, or
 //     dropped into the library by hand, is not fetched back;
 //   - no want already covers it: none open, and none held since its files