fix(merge-boundary): count optional-group pre-merge results as boundary proof - #5

Node.js 20 is deprecated. The following actions target Node.js 20 but are being forced to run on Node.js 24: pnpm/action-setup@v4. For more information see: https://github.blog/changelog/2025-09-19-deprecation-of-node-20-on-github-actions-runners/

Unexpected control character(s) in regular expression: \x00, \x1f