cost: measured Zen2 team row for x86_64-avx2, anchors 2 to 64 (#6 stage 2); threadteam 0.1.2 - #8

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/