[codex][app-server] introduce codex/event/raw_item events (#5578)

codex-rs/app-server/src/codex_message_processor.rs

@@ -1256,7 +1256,10 @@ impl CodexMessageProcessor {
         request_id: RequestId,
         params: AddConversationListenerParams,
     ) {
-        let AddConversationListenerParams { conversation_id } = params;
+        let AddConversationListenerParams {
+            conversation_id,
+            experimental_raw_events,
+        } = params;
         let Ok(conversation) = self
             .conversation_manager
             .get_conversation(conversation_id)
@@ -1293,6 +1296,11 @@ impl CodexMessageProcessor {
                             }
                         };
 
+                        if let EventMsg::RawResponseItem(_) = &event.msg
+                            && !experimental_raw_events {
+                                continue;
+                            }
+
                         // For now, we send a notification for every event,
                         // JSON-serializing the `Event` as-is, but these should
                         // be migrated to be variants of `ServerNotification`