Function scan_multipart_uploads 

pub async fn scan_multipart_uploads(
    client: &Client,
    bucket: &BucketId,
    multipart_table: &MultipartTable,
    older_than_secs: Option<u64>,
) -> Result<Vec<MultipartUpload>, AppError>

List all in-progress multipart uploads for bucket, classify each as Brows3r or Unknown, and optionally filter out uploads younger than older_than_secs.

Algorithm

1. Call list_multipart_uploads to obtain all in-progress uploads.
2. For each upload, check multipart_table.find_by_upload_id:
   • found → MultipartSource::Brows3r
   • not found → MultipartSource::Unknown
3. Apply the older_than_secs threshold — uploads initiated less than older_than_secs seconds ago are excluded from the result.