feat(db): add M6a library-list + artist-tracks queries

Appends ListArtistsAlphaWithCovers, ListAlbumsAlphaWithArtist,
CountAlbums, and ListArtistTracksForUser queries; regenerates sqlc.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

internal/db/queries/albums.sql

@@ -67,3 +67,16 @@ FROM albums
 JOIN artists ON artists.id = albums.artist_id
 ORDER BY albums.created_at DESC, albums.id
 LIMIT $1;
+
+-- name: ListAlbumsAlphaWithArtist :many
+-- M6a: alpha-sorted album list joined with artist_name. Used by
+-- /api/library/albums for the wrapping-grid page. Stable id-tiebreak.
+SELECT sqlc.embed(albums), artists.name AS artist_name
+FROM albums
+JOIN artists ON artists.id = albums.artist_id
+ORDER BY albums.sort_title, albums.id
+LIMIT $1 OFFSET $2;
+
+-- name: CountAlbums :one
+-- M6a: total album count for the /api/library/albums envelope.
+SELECT COUNT(*) FROM albums;