fix(comms): fail-closed inter-agent delivery + check-inbox nudge (#215 PR3) - #853

Node.js 20 is deprecated. The following actions target Node.js 20 but are being forced to run on Node.js 24: github/codeql-action/analyze@v3, github/codeql-action/init@v3. For more information see: https://github.blog/changelog/2025-09-19-deprecation-of-node-20-on-github-actions-runners/