Add core DSC data-tooling gaps: yq, yamllint, git-lfs, xan, pandoc, shellcheck - #12

Node.js 20 is deprecated. The following actions target Node.js 20 but are being forced to run on Node.js 24: actions/checkout@v4. For more information see: https://github.blog/changelog/2025-09-19-deprecation-of-node-20-on-github-actions-runners/

Skipping rustup: most recent version 1.29.0_2 not installed