feat(auto-review) short-circuit (#18890)

## Summary
Short circuit the convo if auto-review hits too many denials

## Testing
- [x] Added unit tests

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Co-authored-by: Codex <noreply@openai.com>

codex-rs/rollout/src/policy.rs

@@ -132,6 +132,7 @@ fn event_msg_persistence_mode(ev: &EventMsg) -> Option<EventPersistenceMode> {
         | EventMsg::DynamicToolCallRequest(_)
         | EventMsg::DynamicToolCallResponse(_) => Some(EventPersistenceMode::Extended),
         EventMsg::Warning(_)
+        | EventMsg::GuardianWarning(_)
         | EventMsg::RealtimeConversationStarted(_)
         | EventMsg::RealtimeConversationSdp(_)
         | EventMsg::RealtimeConversationRealtime(_)