Upload a new supporting document to a workflow

Uploads a single supporting document file and appends it to the workflow's supporting documents collection. Use this endpoint to add one document without affecting the others; use PUT /monitoring-workflows/{workflowId}/supporting-documents to replace the entire collection. The request is a multipart/form-data upload: file is required (the binary content); fileType is required (e.g. 'Medical License'); state is optional; expirationDate is optional and must be in YYYY-MM-DD format when provided — an invalid format returns 400. Requires MONITORING_WORKFLOW_DETAILS_CREATE, MONITORING_WORKFLOW_DETAILS_UPDATE, and MONITORING_WORKFLOW_DETAILS_SUPPORTING_DOCUMENTS_CREATE. The tenant-id header is mandatory.