feat: Phase E E2 example external review packet -- toy data factory with 63 tests, CI-checkable, ERP-TOY-0001 validates all rules - #898

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/