feat: add startAt to response

src/controllers/backup-controller.ts

@@ -79,6 +79,7 @@ export class BackupController extends Controller {
             storageSize: data.bucket.find((b) => a.key.replace(".sql.gz", "") === b.prefix)
               ?.size as number,
             timestamp: a.lastModified as string,
+            startAt: a.paused_until as string,
           }
         : [],
     );