Return agent snapshots from close_agent (#47252)

## What changed

Return an `AgentInfo` snapshot captured before shutdown, including metadata for known unloaded agents. Use the snapshot's status and metadata in the tool's completion event and its status in `previous_status`, replacing the separate status subscription.

Preserve the pre-close status for error reporting when shutdown removes the target before a descendant fails to close. Propagate unexpected thread lookup errors before attempting shutdown.

GitOrigin-RevId: bdbd877aaf0389e830d6a7e84a5e14bb7d47277a

codex-rs/core/src/agent/control/legacy.rs

@@ -1,4 +1,5 @@
 use super::*;
+use crate::agent::api::AgentInfo;
 use codex_protocol::error::CodexErrorDetails;
 use codex_thread_store::PersistContext;
 
@@ -45,12 +46,19 @@ impl LocalAgentControl {
 
     /// Mark `agent_id` as explicitly closed in persisted spawn-edge state, then shut down the
     /// agent and any live descendants reached from the in-memory tree.
-    pub(crate) async fn close_agent(&self, agent_id: ThreadId) -> CodexResult<String> {
+    pub(crate) async fn close_agent(&self, agent_id: ThreadId) -> CodexResult<AgentInfo> {
         let state = self.upgrade()?;
-        let known_agent = self.state.agent_metadata_for_thread(agent_id).is_some();
-        match state.get_thread(agent_id).await {
+        let metadata = self.get_agent_metadata(agent_id);
+        let known_agent = metadata.is_some();
+        let snapshot = match state.get_thread(agent_id).await {
             Ok(thread) => {
-                if !thread.config_snapshot().await.ephemeral
+                let agent = LiveAgent {
+                    thread_id: agent_id,
+                    metadata: metadata.unwrap_or_default(),
+                    status: thread.agent_status().await,
+                };
+                let config = Box::new(thread.config_snapshot().await);
+                if !config.ephemeral
                     && let Some(agent_graph_store) = state.agent_graph_store()
                     && let Err(err) = agent_graph_store
                         .set_thread_spawn_edge_status(
@@ -61,6 +69,7 @@ impl LocalAgentControl {
                 {
                     warn!("failed to persist thread-spawn edge status for {agent_id}: {err}");
                 }
+                AgentInfo::Loaded { agent, config }
             }
             Err(err)
                 if known_agent && matches!(err.details(), CodexErrorDetails::ThreadNotFound(_)) =>
@@ -77,12 +86,10 @@ impl LocalAgentControl {
                         "failed to persist stale thread-spawn edge status for {agent_id}: {err}"
                     )));
                 }
+                AgentInfo::Unloaded(metadata.unwrap_or_default())
             }
-            Err(err) if matches!(err.details(), CodexErrorDetails::ThreadNotFound(_)) => {}
-            Err(err) => {
-                warn!("failed to inspect agent before close {agent_id}: {err}");
-            }
-        }
+            Err(err) => return Err(err),
+        };
         match Box::pin(self.shutdown_agent_tree(agent_id)).await {
             Err(err)
                 if known_agent
@@ -91,9 +98,9 @@ impl LocalAgentControl {
                         CodexErrorDetails::ThreadNotFound(_) | CodexErrorDetails::InternalAgentDied
                     ) =>
             {
-                Ok(String::new())
+                Ok(snapshot)
             }
-            result => result,
+            result => result.map(|_| snapshot),
         }
     }