M1 jobs and scheduling: steps 2–6 (fake executor, scheduler core, job wrapper, K3s executor, job API) - #131

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/