Function emit_session_end 

pub async fn emit_session_end(
    hook_bus: &Arc<HookBus>,
    session_id: &str,
    transcript: Option<Vec<Arc<Value>>>,
    budget: Duration,
) -> bool

Session-level: fire on_session_end for one session — concurrent dispatch (the hook only allows continue, so ordering cannot matter), fail-open under budget. Clears the session’s keyed injection afterwards. Returns false if the budget elapsed (handlers may not have flushed; the transcript is already saved by the caller, so nothing is lost). Per session, not per process: every session in a daemon gets its own end event.