Create or update a rule in the draft

Creates or updates a single rule in the draft. Omit id to create a new rule: the server assigns the id and appends the rule at the end of the evaluation order. Provide an existing id to update that rule in place; only the fields of this request body are written, everything else is preserved. If no draft exists yet, one is created automatically as a copy of the published revision. The response is the full draft with freshly recomputed notices — review them after every change.