Add docusaurus-plugin-copy-page-button

[portdeveloper]

Summary

Adds docusaurus-plugin-copy-page-button to the Fastify website so readers can copy any documentation page as clean markdown — useful when piping plugin docs, hooks, or route options into ChatGPT, Claude, Perplexity, or Gemini.

The plugin auto-injects a small "Copy page" button + dropdown into the doc page's table-of-contents area. The dropdown offers:

• Copy as markdown
• View as markdown
• Open in ChatGPT / Claude / Perplexity / Gemini

Live preview of the UI: https://portdeveloper.github.io/copy-page-button-showcase/

Relationship to existing llms.txt

The website already runs @signalwire/docusaurus-plugin-llms-txt to generate /llms.txt and /llms-full.txt at build time — great for whole-corpus consumption. This PR doesn't replace or duplicate that. The plugin adds the UI affordance: a reader on a specific page can grab just that page's markdown, or one-click open it in an AI tool, without going through the corpus index.

Adoption

The plugin currently ships on docs sites for React Native (just merged via facebook/react-native-website#5085), Puppeteer, Arbitrum, Cardano, Sui, Ethereum execution-apis, and several others — full list in the project README.

Changes

• Added 'docusaurus-plugin-copy-page-button' to the plugins array in docusaurus.config.js
• Added docusaurus-plugin-copy-page-button@^0.6.2 to dependencies
• Resulting package-lock.json updates

Notes

• package-lock.json shows incidental "libc" field removals on a handful of optional native deps. That's npm 10.9.8 (what I ran with) normalizing keys differently from the lockfile's original generator; happy to regenerate with a specific npm version if maintainers want a cleaner diff.
• I did not run the full scripts/build-website.sh locally — it downloads Fastify release artifacts to generate versions.json. The plugin add is a single string in the plugins array, identical to the pattern landed in 4 sibling PRs (Jellyfin, Seeed Studio Wiki, PlayCanvas Developer, Temporal) where the full build was verified.

[portdeveloper]

On reflection, I think this overlaps too much with what Fastify already ships — between @signalwire/docusaurus-plugin-llms-txt generating /llms.txt + /llms-full.txt and the per-page .md URL routes (e.g. https://fastify.dev/docs/latest/Guides/Getting-Started.md returns raw markdown today), readers and AI tools already have a clean path to consume page content. The page-level UI affordance the plugin adds isn't a strong enough net add to justify the dependency. Closing this myself rather than wasting reviewer time. Thanks for the great existing setup!