fix local codex review comment:

  - [P0] Always capture previousResponseId — packages/agents-core/src/run.ts:1791-1796
    When we start a Responses conversation without an explicit conversationId or previousResponseId, trackServerItems should capture the first response ID so that
  follow-up turns can pass it back to the API. The new guard this.previousResponseId !== undefined prevents that first assignment, so previousResponseId stays
  undefined forever and second turn requests go up without any conversation context even though we only send the delta. That means the model loses all history and
  breaks server-managed conversation flows. Please drop that guard and always record the latest response ID whenever conversationId is absent.

Author: seratch

packages/agents-core/src/run.ts

@@ -1799,11 +1799,7 @@ class ServerConversationTracker {
         this.serverItems.add(item);
       }
     }
-    if (
-      !this.conversationId &&
-      this.previousResponseId !== undefined &&
-      modelResponse.responseId
-    ) {
+    if (!this.conversationId && modelResponse.responseId) {
       this.previousResponseId = modelResponse.responseId;
     }
   }