Method cancel_subagent_task

core/src/agent_api.rs:874–876

Cancel an in-flight delegated subagent task by id. Returns `true` when a cancellation token was found and fired, `false` when the task id is unknown or the task has already finished. The eventual `SubagentEnd` from the cancelled child loop won't downgrade the terminal status — it stays `Cancelled`.

(&self, task_id: &str)

    /// `SubagentEnd` from the cancelled child loop won't downgrade the
    /// terminal status — it stays `Cancelled`.
    pub async fn cancel_subagent_task(&self, task_id: &str) -> bool {
        self.subagent_tasks.cancel(task_id).await
    }

    /// Return a shared handle to the session's subagent task tracker.
    ///