fix(web): biorouter web serves no transcripts, gates the turn that reaches a chat, and stops reflecting the URL into script context (#56) - #267

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