fix: a slot the resolver emptied folds only into a copy of its own song (M498)

On 2026-10-20 the emptied "Open the Gateway" slot of Auvic's Speed Demons
was folded by title into another file tagged "Open the Gateway" that holds
Onward (244 s against the song's 254 s), so the album was never wanted
back. A wrong-slot removal now stamps tracks.emptied_at (migration 0095)
when the album holds no copy of the song as long as its MusicBrainz slot,
and missing-pair folding pairs such a row by title only with a track added
since: a copy fetched again. A slot whose song the album does hold (VOID
DLC's Weeper beside Void's) folds into it as before.

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

internal/db/dbq/likes.sql.go

@@ -281,7 +281,7 @@ func (q *Queries) ListLikedTrackIDs(ctx context.Context, userID pgtype.UUID) ([]
 }
 
 const listLikedTrackRows = `-- name: ListLikedTrackRows :many
-SELECT t.id, t.title, t.album_id, t.artist_id, t.track_number, t.disc_number, t.duration_ms, t.file_path, t.file_size, t.file_format, t.bitrate, t.mbid, t.genre, t.added_at, t.updated_at, t.tag_source, t.tag_sources_version, t.tag_read_version, t.missing_since, t.mbid_source, t.song_id, t.song_key, t.source_verdict, t.source_verdict_at FROM tracks t
+SELECT t.id, t.title, t.album_id, t.artist_id, t.track_number, t.disc_number, t.duration_ms, t.file_path, t.file_size, t.file_format, t.bitrate, t.mbid, t.genre, t.added_at, t.updated_at, t.tag_source, t.tag_sources_version, t.tag_read_version, t.missing_since, t.mbid_source, t.song_id, t.song_key, t.source_verdict, t.source_verdict_at, t.emptied_at FROM tracks t
 JOIN (SELECT DISTINCT ON (lt.song_key) l.track_id, l.liked_at
         FROM general_likes l
         JOIN tracks lt ON lt.id = l.track_id
@@ -335,6 +335,7 @@ func (q *Queries) ListLikedTrackRows(ctx context.Context, arg ListLikedTrackRows
 			&i.SongKey,
 			&i.SourceVerdict,
 			&i.SourceVerdictAt,
+			&i.EmptiedAt,
 		); err != nil {
 			return nil, err
 		}