c29fad606c
actions/upload-artifact@v3 is fully deprecated and causes instant CI failure. Also upgrades checkout, setup-python, cache, github-script, and codecov actions to their latest major versions to resolve Node.js 20 deprecation warnings. Adds missing pytest install to MCP Vector DB test job and pins ruff>=0.15 in CI to match local tooling. Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>