#673: Closing a tab activates its neighbour, not the last-used tab — tab_mru is maintained but never consulted (and is index-based, so reorder corrupts it) - #682

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