Operator: approve an agent’s proposal

Operator console only: requires the web session of an address in the operator allowlist of this installation, sent from the application itself. Every other signed-in caller and every valid Bearer token receives 404 NOT_FOUND, whether or not this installation has an operator configured; a caller with no valid credential receives 401, as on every route. Recorded in the operator log. Runs the act the proposal names — the same service the console runs by hand — as this operator; the operator log row says it came from a proposal and names it. 404 for a proposal that does not exist; 409 when it is already decided or expired, its target no longer exists, or its act has nothing left to do on the target as it is now (Nothing left to do: …; the proposal stays open); 400 when the target changed after the proposal and acknowledgeStale is not true, or when the proposal suspends a workspace and confirmSlug does not give the workspace’s slug. It may give a reference: a ticket or card key, never an address.