thumbnail 테이블의 created_at 컬럼의 이름을 updated_at으로 변경

src/lib/server/services/file.ts

@@ -92,7 +92,7 @@ export const getFileThumbnailInformation = async (userId: number, fileId: number
     error(404, "File or its thumbnail not found");
   }
 
-  return { encContentIv: thumbnail.encContentIv };
+  return { updatedAt: thumbnail.updatedAt, encContentIv: thumbnail.encContentIv };
 };
 
 export const getFileThumbnailStream = async (userId: number, fileId: number) => {