Function register_session

core/src/agent_api/agent_sessions.rs:57–65

Register a freshly built session's close handle into the parent agent's registry. Called by `session_builder::build_agent_session` immediately after the handle is constructed. Uses `Weak` so the registry doesn't keep the handle alive; when the caller drops their `AgentSession`, the handle's `Arc` count goes to zero, the handle drops, and the `Weak` in the registry becomes dangling. Dead entries a

(agent: &Agent, handle: &Arc<SessionCloseHandle>)

/// dangling. Dead entries are pruned lazily on the next
/// [`list_sessions`] / [`close_session`] access.
pub(super) fn register_session(agent: &Agent, handle: &Arc<SessionCloseHandle>) {
    let weak = Arc::downgrade(handle);
    let id = handle.session_id.clone();
    let mut sessions = agent
        .sessions
        .lock()
        .unwrap_or_else(|poison| poison.into_inner());
    sessions.insert(id, weak);
}

fn bail_if_agent_closed(agent: &Agent) -> Result<()> {
    if agent.closed.load(std::sync::atomic::Ordering::Acquire) {