Updates the dynamic field values of an existing client. This endpoint does not change the client's identification attributes (name, document, data returned from external sources) — it is the mechanism for writing answers into the fields configured by the company (the same set from the Client Configuration domain), the same way they are filled in when the client is created.The ag-flow-id header is optional on these calls; when provided, it identifies an existing company flow (available from GET /v1/flows, Flow domain, or from the flow's URL in the AgFlow application) — omitting it does not block the call.