feat: deprecation warning (#5825)

<img width="955" height="311" alt="Screenshot 2025-10-28 at 14 26 25"
src="https://github.com/user-attachments/assets/99729b3d-3bc9-4503-aab3-8dc919220ab4"
/>

codex-rs/core/src/rollout/policy.rs

@@ -75,6 +75,7 @@ pub(crate) fn should_persist_event_msg(ev: &EventMsg) -> bool {
         | EventMsg::PlanUpdate(_)
         | EventMsg::ShutdownComplete
         | EventMsg::ViewImageToolCall(_)
+        | EventMsg::DeprecationNotice(_)
         | EventMsg::ItemStarted(_)
         | EventMsg::ItemCompleted(_) => false,
     }