Function object_create_folder 

pub async fn object_create_folder(
    profile_id: ProfileId,
    bucket: BucketId,
    prefix: String,
    store: State<'_, ProfileStoreHandle>,
    pool: State<'_, S3ClientPoolHandle>,
    locks: State<'_, LockRegistryHandle>,
    cache: State<'_, CacheHandle>,
    channel: AppHandle,
) -> Result<(), AppError>

Create a virtual folder placeholder at bucket/prefix/.

Acquires a lock on the prefix, calls create_folder, then emits objects:updated for the parent prefix.