Support MCP in packaged Python runtime

.github/workflows/python-release.yml

@@ -72,6 +72,7 @@ jobs:
         run: |
           python -m pip install --find-links dist "deepseek-harness-sdk==${{ steps.compatibility-version.outputs.version }}"
           python scripts/smoke-python-runtime.py --scenario sdk-default
+          python scripts/smoke-python-runtime.py --scenario sdk-mcp
 
   validate:
     name: Validate release candidate