test: 消除 afterMonotonic 基线假红，重建 -j4 稳定对照基线（#115 / #116） - #117

Node.js 20 is deprecated. The following actions target Node.js 20 but are being forced to run on Node.js 24: actions/cache/restore@v4. For more information see: https://github.blog/changelog/2025-09-19-deprecation-of-node-20-on-github-actions-runners/