Negative result: P112 fixed-reader two-total COPY at source union 48 — two-column loss bound exactly 5 (attained), full-rank lower bound 65, COPY >= 64 extends (PR2382 OQ1) - #2581

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/