feat(config): default to WebSocket and migrate saved HTTP settings

tests/unit/test_openai_responses.py

@@ -43,6 +43,9 @@ def transport_model(monkeypatch):
     from langchain_openai import ChatOpenAI
     import openai
 
+    # These fixtures exercise the explicitly selected HTTP compatibility path.
+    monkeypatch.setattr(settings, "OPENAI_TRANSPORT", "http")
+
     requests = []
     outputs = []