feat: 房间 24 小时自动过期，添加 TTL 清理机制

prisma/migrations/20260224114226_add_room_ttl/migration.sql

@@ -0,0 +1,20 @@
+/*
+  Warnings:
+
+  - Added the required column `expiresAt` to the `Room` table without a default value. This is not possible if the table is not empty.
+
+*/
+-- RedefineTables
+PRAGMA defer_foreign_keys=ON;
+PRAGMA foreign_keys=OFF;
+CREATE TABLE "new_Room" (
+    "id" TEXT NOT NULL PRIMARY KEY,
+    "data" TEXT NOT NULL,
+    "createdAt" DATETIME NOT NULL DEFAULT CURRENT_TIMESTAMP,
+    "expiresAt" DATETIME NOT NULL
+);
+INSERT INTO "new_Room" ("createdAt", "data", "id", "expiresAt") SELECT "createdAt", "data", "id", "createdAt" FROM "Room";
+DROP TABLE "Room";
+ALTER TABLE "new_Room" RENAME TO "Room";
+PRAGMA foreign_keys=ON;
+PRAGMA defer_foreign_keys=OFF;