fix(mcp): derive gateway WebSocket URL from template port - #351

Node.js 20 is deprecated. The following actions target Node.js 20 but are being forced to run on Node.js 24: trustgraph-ai/contributor-license-agreement/action@main. For more information see: https://github.blog/changelog/2025-09-19-deprecation-of-node-20-on-github-actions-runners/