Narrow AUTO_INCREMENT ids from cluster range claims; log-cursor anti-entropy; per-row last-writer-wins (fixes #170) - #175

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-go@v5, actions/upload-artifact@v4. For more information see: https://github.blog/changelog/2025-09-19-deprecation-of-node-20-on-github-actions-runners/