chore(auto-review) feature => stable (#19063)

## Summary
Turn on Auto Review

## Testing
- [x] Update unit tests

codex-rs/core/src/config/config_tests.rs

@@ -3628,8 +3628,7 @@ async fn set_feature_enabled_updates_profile() -> anyhow::Result<()> {
 }
 
 #[tokio::test]
-async fn set_feature_enabled_persists_default_false_feature_disable_in_profile()
--> anyhow::Result<()> {
+async fn set_feature_enabled_persists_feature_disable_in_profile() -> anyhow::Result<()> {
     let codex_home = TempDir::new()?;
 
     ConfigEditsBuilder::new(codex_home.path())
@@ -6881,7 +6880,7 @@ smart_approvals = true
         .build()
         .await?;
 
-    assert!(!config.features.enabled(Feature::GuardianApproval));
+    assert!(config.features.enabled(Feature::GuardianApproval));
     assert_eq!(config.approvals_reviewer, ApprovalsReviewer::User);
 
     let serialized = tokio::fs::read_to_string(codex_home.path().join(CONFIG_TOML_FILE)).await?;
@@ -6910,7 +6909,7 @@ smart_approvals = true
         .build()
         .await?;
 
-    assert!(!config.features.enabled(Feature::GuardianApproval));
+    assert!(config.features.enabled(Feature::GuardianApproval));
     assert_eq!(config.approvals_reviewer, ApprovalsReviewer::User);
 
     let serialized = tokio::fs::read_to_string(codex_home.path().join(CONFIG_TOML_FILE)).await?;