feat: add wait tool implementation for collab (#9088)

Add implementation for the `wait` tool.

For this we consider all status different from `PendingInit` and
`Running` as terminal. The `wait` tool call will return either after a
given timeout or when the tool reaches a non-terminal status.

A few points to note:
* The usage of a channel is preferred to prevent some races (just
looping on `get_status()` could "miss" a terminal status)
* The order of operations is very important, we need to first subscribe
and then check the last known status to prevent race conditions
* If the channel gets dropped, we return an error on purpose

codex-rs/core/src/codex_delegate.rs

@@ -87,7 +87,7 @@ pub(crate) async fn run_codex_thread_interactive(
         next_id: AtomicU64::new(0),
         tx_sub: tx_ops,
         rx_event: rx_sub,
-        agent_status: Arc::clone(&codex.agent_status),
+        agent_status: codex.agent_status.clone(),
     })
 }
 
@@ -129,7 +129,7 @@ pub(crate) async fn run_codex_thread_one_shot(
     // Bridge events so we can observe completion and shut down automatically.
     let (tx_bridge, rx_bridge) = async_channel::bounded(SUBMISSION_CHANNEL_CAPACITY);
     let ops_tx = io.tx_sub.clone();
-    let agent_status = Arc::clone(&io.agent_status);
+    let agent_status = io.agent_status.clone();
     let io_for_bridge = io;
     tokio::spawn(async move {
         while let Ok(event) = io_for_bridge.next_event().await {
@@ -363,20 +363,23 @@ mod tests {
     use super::*;
     use async_channel::bounded;
     use codex_protocol::models::ResponseItem;
+    use codex_protocol::protocol::AgentStatus;
     use codex_protocol::protocol::RawResponseItemEvent;
     use codex_protocol::protocol::TurnAbortReason;
     use codex_protocol::protocol::TurnAbortedEvent;
     use pretty_assertions::assert_eq;
+    use tokio::sync::watch;
 
     #[tokio::test]
     async fn forward_events_cancelled_while_send_blocked_shuts_down_delegate() {
         let (tx_events, rx_events) = bounded(1);
         let (tx_sub, rx_sub) = bounded(SUBMISSION_CHANNEL_CAPACITY);
+        let (_agent_status_tx, agent_status) = watch::channel(AgentStatus::PendingInit);
         let codex = Arc::new(Codex {
             next_id: AtomicU64::new(0),
             tx_sub,
             rx_event: rx_events,
-            agent_status: Default::default(),
+            agent_status,
         });
 
         let (session, ctx, _rx_evt) = crate::codex::make_session_and_context_with_rx().await;