Method cancel

core/src/subagent_task_tracker.rs:129–156

Fire the registered token and mark the snapshot as `Cancelled`. Returns `true` if a token was found (caller can interpret as "cancellation initiated"), `false` if the task id was unknown or the task already finished. The eventual `SubagentEnd` event won't overwrite the Cancelled status — see `record_event`.

(&self, task_id: &str)

    /// the task already finished. The eventual `SubagentEnd` event won't
    /// overwrite the Cancelled status — see `record_event`.
    pub async fn cancel(&self, task_id: &str) -> bool {
        let token = self.cancellers.write().await.remove(task_id);
        match token {
            Some(token) => {
                token.cancel();
                let now = now_ms();
                let transitioned = {
                    let mut tasks = self.tasks.write().await;
                    if let Some(entry) = tasks.get_mut(task_id) {
                        if entry.status == SubagentStatus::Running {
                            entry.status = SubagentStatus::Cancelled;
                            entry.updated_ms = now;
                            true
                        } else {
                            false
                        }
                    } else {
                        false
                    }
                };
                if transitioned {
                    self.mark_terminal_and_evict(task_id).await;
                }
                true
            }
            None => false,
        }
    }

    /// Apply a single agent event to the tracker. Non-subagent events are ignored.
    pub async fn record_event(&self, event: &AgentEvent) {