Previous image (rust:1.83-bookworm) lacks Node.js, causing GitHub Actions
to fail with: 'exec: "node": executable file not found'
Solution:
- Change rust runner image from rust:1.83-bookworm to docker:27-cli
- docker:27-cli includes: Node.js, git, docker CLI, full dev tools
- Verified tag exists: docker manifest inspect docker:27-cli ✓
This allows actions/checkout@v4 and other GitHub Actions to run properly
on the rust runner pod.