Support configurable timeouts for thread shell commands (#41384)

## What changed

- Add an optional `timeoutMs` parameter to `thread/shellCommand` and propagate it to user shell execution.
- Preserve the one-hour default when the parameter is omitted or `null`, allow longer deadlines, and treat `0` as an immediate timeout.
- Reject negative or otherwise invalid values before execution. Timing out an auxiliary shell command leaves its active turn running.

## Testing

- Cover default, extended, immediate, invalid, standalone, active-turn, and interruption behavior.

GitOrigin-RevId: d72f67793d9766b7383f28d30140270a4a76a495

codex-rs/core/src/session/handlers.rs

@@ -95,7 +95,12 @@ pub async fn inter_agent_communication(
     }
 }
 
-pub async fn run_user_shell_command(sess: &Arc<Session>, sub_id: String, command: String) {
+pub async fn run_user_shell_command(
+    sess: &Arc<Session>,
+    sub_id: String,
+    command: String,
+    timeout_ms: Option<u64>,
+) {
     if let Some((turn_context, cancellation_token)) =
         sess.active_turn_context_and_cancellation_token().await
     {
@@ -105,6 +110,7 @@ pub async fn run_user_shell_command(sess: &Arc<Session>, sub_id: String, command
                 session,
                 turn_context,
                 command,
+                timeout_ms,
                 cancellation_token,
                 UserShellCommandMode::ActiveTurnAuxiliary,
             )
@@ -116,8 +122,12 @@ pub async fn run_user_shell_command(sess: &Arc<Session>, sub_id: String, command
     let turn_context = sess
         .new_turn_with_default_settings(sub_id, Default::default())
         .await;
-    sess.spawn_task(turn_context, Vec::new(), UserShellCommandTask::new(command))
-        .await;
+    sess.spawn_task(
+        turn_context,
+        Vec::new(),
+        UserShellCommandTask::new(command, timeout_ms),
+    )
+    .await;
 }
 
 pub async fn resolve_elicitation(
@@ -675,8 +685,11 @@ pub(super) async fn submission_loop(
                     set_thread_memory_mode(&sess, sub.id.clone(), mode).await;
                     false
                 }
-                Op::RunUserShellCommand { command } => {
-                    run_user_shell_command(&sess, sub.id.clone(), command).await;
+                Op::RunUserShellCommand {
+                    command,
+                    timeout_ms,
+                } => {
+                    run_user_shell_command(&sess, sub.id.clone(), command, timeout_ms).await;
                     false
                 }
                 Op::ResolveElicitation {