SiteStagedUploadFile
Any unique client-chosen id echoed with the staged file_id for correlation. Not used server-side beyond the response.
Staged upload identifier for use in create, update, or file operations after uploading bytes to S3. The id can be reused for 1 hour from presign, each attach copies the bytes into that site's bundle, a repeat attach before expiry creates another bundle, and the staged object is removed after expiry.
Staged file name from the presign file_name intent.
Upload status. Returns awaiting_upload after presign until the file is uploaded to S3. After the object exists in S3, status becomes active on first use. Attach does not consume the staged upload; it is removed after expiry.
Presigned S3 POST URL for uploading the file bytes.
Form fields required for the S3 POST (send these before the file part).