#821: Adopt quadraui render_markdown_to_styled for hover popups — 0 uses today, ~350 lines of regex markdown - #848

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/