feat: align with upstream 1.5.9.9

server/utils/scheduleSongPool.ts

@@ -0,0 +1,13 @@
+import { db } from '~/drizzle/db'
+import { scheduleSongPool, songs } from '~/drizzle/schema'
+import { eq, count } from 'drizzle-orm'
+
+// 返回备选池有效记录数（innerJoin 排除歌曲已删除的孤立记录）
+export const fetchPoolCount = async () => {
+  const result = await db
+    .select({ count: count() })
+    .from(scheduleSongPool)
+    .innerJoin(songs, eq(scheduleSongPool.songId, songs.id))
+    .limit(1)
+  return result[0]?.count || 0
+}