use std::future::Future;use std::pin::Pin;use codex_protocol::ThreadId;/// Future returned by one injected subagent-spawn helper.pub type AgentSpawnFuture<'a, T, E> = Pin<Box<dyn Future<Output = Result<T, E>> + Send + 'a>>;/// Constructor-injected host helper for extensions that need to spawn subagents.////// The extension owns the request shape and resulting handle types. The host/// provides the implementation when it constructs the extension.pub trait AgentSpawner<R>: Send + Sync {    type Spawned;    type Error;    fn spawn_subagent<'a>(        &'a self,        forked_from_thread_id: ThreadId,        request: R,    ) -> AgentSpawnFuture<'a, Self::Spawned, Self::Error>;}impl<R, S, E, F> AgentSpawner<R> for Fwhere    F: Fn(ThreadId, R) -> AgentSpawnFuture<'static, S, E> + Send + Sync,{    type Spawned = S;    type Error = E;    fn spawn_subagent<'a>(        &'a self,        forked_from_thread_id: ThreadId,        request: R,    ) -> AgentSpawnFuture<'a, Self::Spawned, Self::Error> {        self(forked_from_thread_id, request)    }}