[j-atkins]

There is a backlog of dependabot PRs. In this PR, I directed an LLM to solve all of them in one branch and generally bring up to date.

@erikvansebille I will leave this PR here, please do feel free to take it over and merge once you've had time to look and check this is how you'd like to handle the backlog 🙂

This is the description from the LLM:

Summary

This PR combines the backlog of dependabot updates into one. It upgrades the GitHub Actions and the npm dependencies, including Next 14→16 and React 18→19. It also makes the small fixes those upgrades needed: a new lint config, building with webpack, and gitignoring next-env.d.ts. Most of the large line count is the regenerated package-lock.json. Chakra UI stays at v2 and ESLint at v9, because their newest versions would break the site.

Included

• GitHub Actions: checkout 5, setup-node 6, upload-artifact 5, upload-pages-artifact 4, lychee-action 2.7.0
• npm "dependencies" and "dev-dependencies" groups: Next 16, React 19, etc.
• feed 5.2.1 (RSS items now include authors)
• glob, typescript and webpack are already covered by the regenerated lockfile

Differences from the dependabot PRs

• @chakra-ui/react stays at v2 (v3 is a breaking rewrite and needs its own PR)
• eslint stays at v9 (the Next plugins don't support v10 yet)
• dev and build use --webpack (Turbopack rejects the MDX options)
• Lint moved to a flat config because next lint was removed. This also surfaced a missing Image import in project-card.js, which is fixed.
• next-env.d.ts is now gitignored (Next 16 regenerates it on every run)

Testing

• npm run build, npm run lint and npm run dev work locally, and the site was clicked through in the browser (including the blog). The Actions upgrades will only be exercised by CI.

Note also the majority of the (very many) line changes come from the package-lock.json file.