Upgrade Docusaurus 2.4.3 -> 3.10.2, clearing all website vulnerabilities (#193)

[StefanSteiner]

Migrates the docs site to Docusaurus 3, which refreshes the transitive dependency tree and resolves 66 of the 68 Dependabot advisories natively. The remaining two (serialize-javascript, uuid) are pinned via resolutions. Net result: yarn audit reports 0 vulnerabilities.

Changes:

• Bump @docusaurus/* to ^3.10.2, react/react-dom to ^18, @mdx-js/react to ^3, prism-react-renderer to ^2; swap @tsconfig/docusaurus for @docusaurus/tsconfig; add @types/react ^18; bump typescript to ~5.6.3.
• Drop the Docusaurus 2 resolutions patchwork (incl. the webpack 5.94.0 pin, which was only needed to dodge 2.4.3's schema-utils v4 build break); keep only serialize-javascript + uuid pins and an @types/react dedupe.
• prism-react-renderer v2 import (themes.github).
• MDX v3: convert installation.md Tabs from the mdx-code-block idiom to native JSX; DownloadPicker uses a documented cast since v3 narrows TabItem.label to string while still rendering ReactNode.
• Migrate onBrokenMarkdownLinks to markdown.hooks; add onBrokenAnchors: 'throw' and fix a pre-existing broken anchor in releases.md.
• Add a ts-node CommonJS override so the deploy step's download_links.ts still runs under the new esnext module config.

Verified: yarn install --frozen-lockfile, lint:check, typecheck, build, ts-node download_links.ts, and yarn audit (0 vulnerabilities) all pass; Tabs and DownloadPicker icons render correctly in the built HTML.