chore(context) Include guardian approval context (#15366)

## Summary
Include the guardian context in the developer message for approvals

## Testing
- [x] Updated unit tests

codex-rs/core/tests/suite/permissions_messages.rs

@@ -493,6 +493,7 @@ async fn permissions_message_includes_writable_roots() -> Result<()> {
     let expected = DeveloperInstructions::from_policy(
         &sandbox_policy,
         AskForApproval::OnRequest,
+        test.config.approvals_reviewer,
         &Policy::empty(),
         test.config.cwd.as_path(),
         false,