Translates a natural-language audience description into a ClickFunnels contact filter using an AI model.

The response always includes the same key set: a stable_id token, a structured filter object, and the
identity fields id, public_id, workspace_id, and name. When save: true is supplied the filter is
persisted as a reusable Refine::StoredFilter and those identity fields are populated; otherwise they are
null. A saved filter can be fetched later via GET /api/v2/contacts/filters/{id}.

Pass the returned stable_id to GET /api/v2/workspaces/{workspace_id}/contacts as
?stable_id=…, or pass the returned id as ?stored_filter_id=… (requires save: true).

The stable_id token uses the standard gzip+base64 Refine full-state format — the same format the
server-rendered filter UI produces and consumes — making tokens fully interoperable between the API
and the HTML filter UI.