[GRDM-62705] ENABLE_TIMESTAMP = False でタイムスタンプ局へのリクエストを完全に停止できるように修正 - #783

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/upload-artifact@v4. For more information see: https://github.blog/changelog/2025-09-19-deprecation-of-node-20-on-github-actions-runners/