fix(image-upload): correct folder naming in buildStorageKey method

apps/box-mgnt-api/src/mgnt-backend/feature/image-upload/image-upload.service.ts

@@ -85,7 +85,7 @@ export class ImageUploadService {
    * Build canonical storage key: <folder>/<yyyy>/<MM>/<dd>/<uuid>.<ext>
    */
   private buildStorageKey(type: ImageType, originalName: string): string {
-    const folder = type === 'ads-cover' ? 'ads-covers' : 'video-covers';
+    const folder = type === 'ads-cover' ? 'ads-cover' : 'video-cover';
     const now = new Date();
     const yyyy = now.getFullYear();
     const MM = String(now.getMonth() + 1).padStart(2, '0');