feat(db): add paged + count queries for library reads

internal/db/queries/artists.sql

@@ -24,3 +24,16 @@ SELECT * FROM artists
 WHERE name ILIKE '%' || $1 || '%'
 ORDER BY sort_name
 LIMIT $2 OFFSET $3;
+
+-- name: ListArtistsAlpha :many
+SELECT * FROM artists ORDER BY sort_name, name, id LIMIT $1 OFFSET $2;
+
+-- name: ListArtistsNewest :many
+-- Secondary id tiebreaker keeps pagination stable when created_at ties.
+SELECT * FROM artists ORDER BY created_at DESC, id DESC LIMIT $1 OFFSET $2;
+
+-- name: CountArtists :one
+SELECT COUNT(*) FROM artists;
+
+-- name: CountArtistsMatching :one
+SELECT COUNT(*) FROM artists WHERE name ILIKE '%' || $1::text || '%';