[ci][test] Improve requirements.txt, enable psutil and numba - #17

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, actions/setup-python@v5, actions/upload-artifact@v4. For more information see: https://github.blog/changelog/2025-09-19-deprecation-of-node-20-on-github-actions-runners/

no ../.github/valgrind/clang21-valgrind.supp

flavor=system source=package-manager prefix=/home/runner/work/cppjit/cppjit/install

flavor=system: llvm-21 on noble