fix(auto-review) skip legacy notify for auto review threads (#24714)

## Summary
Clear inherited legacy `notify` from Guardian review session config,
since we should not be passing auto review threads into `notify`
targets. Keeps legacy notify payload and hook runtime behavior unchanged
for normal user turns.

## Testing
- [x] add a Guardian config regression and dedicated Guardian
integration test so review sessions cannot inherit parent notify hooks

codex-rs/core/src/guardian/review_session.rs

@@ -905,6 +905,7 @@ pub(crate) fn build_guardian_review_session_config(
             .map(guardian_policy_prompt_with_config)
             .unwrap_or_else(guardian_policy_prompt),
     );
+    guardian_config.notify = None;
     guardian_config.developer_instructions = None;
     guardian_config.permissions.approval_policy = Constrained::allow_only(AskForApproval::Never);
     guardian_config

codex-rs/core/src/guardian/tests.rs

@@ -2215,6 +2215,25 @@ async fn guardian_review_session_config_clears_parent_developer_instructions() {
     );
 }
 
+#[tokio::test]
+async fn guardian_review_session_config_clears_legacy_notify() {
+    let mut parent_config = test_config().await;
+    parent_config.notify = Some(vec![
+        "/path/to/notify".to_string(),
+        "turn-ended".to_string(),
+    ]);
+
+    let guardian_config = build_guardian_review_session_config_for_test(
+        &parent_config,
+        /*live_network_config*/ None,
+        "active-model",
+        /*reasoning_effort*/ None,
+    )
+    .expect("guardian config");
+
+    assert_eq!(guardian_config.notify, None);
+}
+
 #[tokio::test]
 async fn guardian_review_session_config_uses_live_network_proxy_state() {
     let mut parent_config = test_config().await;