feat(finance/proto): add machine_id field to MBHead for cost resolution - #49

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, bufbuild/buf-setup-action@v1. For more information see: https://github.blog/changelog/2025-09-19-deprecation-of-node-20-on-github-actions-runners/