Simplify numeric common-type selection - #240

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 `src/fpy/bytecode/__init__.py` because appears to be a binary file ('inode/x-empty'). (binary-file)