File and directory helpers on std::filesystem; mkdir() without the shell (#323) (4.2.31) - #787

Node.js 20 is deprecated. The following actions target Node.js 20 but are being forced to run on Node.js 24: actions/cache@v4, actions/checkout@v4, actions/upload-artifact@v4, LouisBrunner/diff-action@v0.2.0. For more information see: https://github.blog/changelog/2025-09-19-deprecation-of-node-20-on-github-actions-runners/