feat(llm): support incremental Responses WebSocket transport

tests/unit/admin_console/test_model_settings.py

@@ -21,6 +21,7 @@ def isolated_settings(monkeypatch, tmp_path):
         "OPENAI_MODEL",
         "OPENAI_BASE_URL",
         "OPENAI_TIMEOUT_SECONDS",
+        "OPENAI_TRANSPORT",
         "OPENAI_MAX_RETRIES",
         "OPENAI_RETRY_INTERVAL_SECONDS",
         "OPENAI_RATE_LIMIT_RETRY_SECONDS",
@@ -50,6 +51,7 @@ def isolated_settings(monkeypatch, tmp_path):
 
 def test_save_reload_and_blank_key_preserves_secret(isolated_settings):
     update = service.ModelSettingsUpdate(
+        transport="websocket",
         base_url="https://gateway.example/v1/",
         model="my-model",
         api_key="new-test-secret",
@@ -63,6 +65,9 @@ def test_save_reload_and_blank_key_preserves_secret(isolated_settings):
     )
     result = service.save_model_settings(update)
     assert result["api_key_configured"]
+    assert result["transport"] == "websocket"
+    assert dotenv_values(isolated_settings)["OPENAI_TRANSPORT"] == "websocket"
+    assert service.ModelSettingsUpdate(model="test").transport is None
     assert "new-test-secret" not in repr(result)
     saved = dotenv_values(isolated_settings)
     assert saved["OPENAI_API_KEY"] == "new-test-secret"