Revoke the sign-in key this request is made with (sign out).

The key in the Authorization header revokes ITSELF: sleeperhit logout, the MCP logout tool, and every new sign-in (which revokes the key the previous one saved) call this, so signing out ends the key on the server rather than only deleting it from one machine. Needs no scope, so a narrowed sign-in key can still end itself. Only a key minted by a browser sign-in (the device flow) can: a key made on the API page answers 409 not_a_sign_in_key and keeps working, and an OAuth connector is disconnected from the API page instead. A key that is already revoked or expired answers 401. The key gives up any standing approval it held, as a revoke from the API page does. Uses the common error envelope. Free.