## Summary
- Rewrites the README quickstart with accurate, tested setup steps (Docker prerequisite, venv/uv usage)
- Moves the "developing from source" instructions into CONTRIBUTING.md
- Removes the manual cluster deploy step from quickstart (cluster bootstraps automatically on sandbox create)
- Fixes empty bash array expansion in Docker build scripts that broke on macOS default bash 3.2 (`set -u` treats `"${EMPTY_ARRAY[@]}"` as unbound)
## Changes
- **README.md**: Replace placeholder quickstart with working install and sandbox create steps; remove manual cluster deploy step since it happens automatically
- **CONTRIBUTING.md**: Add "developing from source" section with mise setup instructions
- **build/scripts/docker-build-cluster.sh**: Use `${arr[@]+"${arr[@]}"}` pattern for safe empty array expansion
- **build/scripts/docker-build-component.sh**: Same fix
Kirit Thadaka