Project pinned schedule slots and validate fixed child outcomes - #29

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. For more information see: https://github.blog/changelog/2025-09-19-deprecation-of-node-20-on-github-actions-runners/

Failed to save: Unable to reserve cache with key setup-uv-2-x86_64-unknown-linux-gnu-ubuntu-24.04-3.11.17-37e0f2373834f1d342599781af3a59fca018b9483b05f5d3b19f55c99293432e, another job may be creating this cache.