Pin eslint to 9.39.4 in docs/docusaurus and regenerate lockfile (PR #2519)

[WilliamBerryiii]

Task

Pin eslint back to 9.39.4 in docs/docusaurus and regenerate that project's lockfile.

Why

PR #2519 bumps eslint to 10.8.0, but eslint-plugin-jsx-a11y@6.10.2 declares a peer range that stops at ^9. This makes npm ci fail with ERESOLVE in the "Docusaurus Unit Tests" check, before any test runs. 6.10.2 is the latest published release of that plugin, so there is no compatible version to upgrade into. Upstream tracking: jsx-eslint/eslint-plugin-jsx-a11y#1075

This change cannot be made locally because the contributor machine cannot reach https://registry.npmjs.org/, and the reachable internal mirror omits dist.integrity, which downgrades lockfile hashes to sha1 and fails npm run lint:public-dependency-feeds.

Scope

Branch: dependabot/npm_and_yarn/npm-dependencies-c586aca45b

Make exactly these changes:

1. In docs/docusaurus/package.json, set devDependencies.eslint to 9.39.4 (currently 10.8.0).
2. Regenerate docs/docusaurus/package-lock.json to match.

Suggested commands:

npm --prefix docs/docusaurus pkg set devDependencies.eslint=9.39.4
npm --prefix docs/docusaurus install --package-lock-only

Commit and push to the same branch. Do not open a new PR.

Do not change

• Any other dependency in docs/docusaurus/package.json. The PR's other updates must stay exactly as they are: @docusaurus/* 3.10.2, react/react-dom 19.2.8, @testing-library/jest-dom 7.0.0, jest-axe 11.0.0, @playwright/test 1.62.0, @happy-dom/jest-environment 20.11.1, @typescript-eslint/parser 8.65.0, ts-jest 29.4.12, wait-on 9.1.0.
• eslint-plugin-jsx-a11y — leave at 6.10.2.
• Root package.json / package-lock.json.
• evals/beval/**.
• .github/dependabot.yml.
• audit-ci.json.
• The .npmrc files in docs/docusaurus/ and evals/beval/.

Acceptance criteria

• docs/docusaurus/package.json shows "eslint": "9.39.4".
• cd docs/docusaurus && npm ci completes without ERESOLVE.
• cd docs/docusaurus && npm test passes.
• npm run lint:public-dependency-feeds passes from the repository root.
• In docs/docusaurus/package-lock.json, every integrity value starts with sha512- and every resolved URL points at registry.npmjs.org. No entry may reference pkgs.visualstudio.com, packagefeedproxy.microsoft.io, or any other non-public host.
• git diff touches only docs/docusaurus/package.json and docs/docusaurus/package-lock.json.