Introduce ModelsManager and migrate app-server to use it. (#7552)

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

@@ -51,7 +51,6 @@ pub(crate) fn should_persist_event_msg(ev: &EventMsg) -> bool {
         | EventMsg::Warning(_)
         | EventMsg::TaskStarted(_)
         | EventMsg::TaskComplete(_)
-        | EventMsg::ListModelsResponse(_)
         | EventMsg::AgentMessageDelta(_)
         | EventMsg::AgentReasoningDelta(_)
         | EventMsg::AgentReasoningRawContentDelta(_)