Delegate review to codex instance (#5572)

In this PR, I am exploring migrating task kind to an invocation of
Codex. The main reason would be getting rid off multiple
`ConversationHistory` state and streamlining our context/history
management.

This approach depends on opening a channel between the sub-codex and
codex. This channel is responsible for forwarding `interactive`
(`approvals`) and `non-interactive` events. The `task` is responsible
for handling those events.

This opens the door for implementing `codex as a tool`, replacing
`compact` and `review`, and potentially subagents.

One consideration is this code is very similar to `app-server` specially
in the approval part. If in the future we wanted an interactive
`sub-codex` we should consider using `codex-mcp`

codex-rs/core/src/tasks/mod.rs

@@ -16,6 +16,7 @@ use tokio_util::task::AbortOnDropHandle;
 use tracing::trace;
 use tracing::warn;
 
+use crate::AuthManager;
 use crate::codex::Session;
 use crate::codex::TurnContext;
 use crate::protocol::EventMsg;
@@ -50,6 +51,10 @@ impl SessionTaskContext {
     pub(crate) fn clone_session(&self) -> Arc<Session> {
         Arc::clone(&self.session)
     }
+
+    pub(crate) fn auth_manager(&self) -> Arc<AuthManager> {
+        Arc::clone(&self.session.services.auth_manager)
+    }
 }
 
 /// Async task that drives a [`Session`] turn.
@@ -123,7 +128,7 @@ impl Session {
                         task_cancellation_token.child_token(),
                     )
                     .await;
-
+                session_ctx.clone_session().flush_rollout().await;
                 if !task_cancellation_token.is_cancelled() {
                     // Emit completion uniformly from spawn site so all tasks share the same lifecycle.
                     let sess = session_ctx.clone_session();