fix: health readiness/liveness split, service-auth key rotation, transport-aware CSRF Secure flag, and reqId in error bodies (#562, #555, #560, #558) - #641

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, actions/setup-node@v4, pnpm/action-setup@v4. For more information see: https://github.blog/changelog/2025-09-19-deprecation-of-node-20-on-github-actions-runners/