notify-session

One-way out-of-turn session notification. Mirrors the legacy session/update JSON-RPC method for events that don't belong to any in-flight prompt-turn (e.g. an agent-emitted available-commands-update advertised during session startup, or a current-mode-update reflecting a mode flip the user triggered out-of-band).

notify-session: async func(session-id: session-id, update: session-update);