feat(Foundations): List.getD_append_cons_length and getD_append_cons_of_ne (supplier for #1037) - #1065

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/