🛠️ Repo: Ensure `npm i` works for all supported Node versions, including devDeps

### Tooling Suggestion Checklist - [x] I have tried restarting my IDE and the issue persists. - [x] I have pulled the latest `main` branch of the repository. - [x] I have read and agree to Mocha's [Code of Conduct](https://github.com/mochajs/mocha/blob/main/.github/CODE_OF_CONDUCT.md) and [Contributing Guidelines](https://github.com/mochajs/mocha/blob/main/.github/CONTRIBUTING.md) - [x] I have searched for [related issues](https://github.com/mochajs/mocha/issues?q=is%3Aissue) and [issues with the `faq` label](https://github.com/mochajs/mocha/issues?utf8=%E2%9C%93&q=is%3Aissue%20label%3Afaq%20), but none matched my issue. - [x] I want to provide a PR to resolve this ### Overview Parent issue #6038 was opened because `npm i` started failing after merging a PR that upgraded a devDep to a version that only supported Node 22.22+, going against Mocha's support of Node 20.19+. Some CI check should've failed in this case, we should investigate and build gates to prevent this from happening again. ### Additional Info The breaking change was not documented. This doesn't excuse my choice to merge without fully vetting the changes, though! Filed a bug on the upstream repo.