site3: add docusaurus-plugin-copy-page-button

[portdeveloper]

What this adds

A "Copy page" button in the docs sidebar that exports the current Apache BookKeeper docs page as clean markdown, with one-click "Open in ChatGPT", "Open in Claude", and "Open in Gemini" actions.

Why for BookKeeper

BookKeeper is the kind of distributed systems codebase that devs ask AI assistants about constantly: protocol details, configuration tuning, deployment patterns, and the various API surface for the client SDKs. A one-click handoff from any docs page into Claude or ChatGPT removes the friction of "select all, strip out the nav, paste."

The plugin auto-injects into the table-of-contents sidebar — no further config needed and no new build step.

Production users

The plugin is currently shipping on Ethereum execution-apis, Sui (Mysten Labs), Walrus, Seal, SuiNS, Monad, Flare, Kaia, Nillion, Chronicle, Cardano, Kurtosis, and Dagger docs. ~10k npm installs/month.

Changes

• Adds docusaurus-plugin-copy-page-button to site3/website/package.json dependencies
• Adds the plugin string to the existing plugins array in site3/website/docusaurus.config.js

Links

• Live demo: https://portdeveloper.github.io/copy-page-button-showcase/
• Plugin repo: https://github.com/portdeveloper/docusaurus-plugin-copy-page-button
• npm: https://www.npmjs.com/package/docusaurus-plugin-copy-page-button

Happy to revert or adjust if this doesn't fit the project's direction.

[portdeveloper]

Friendly bump — happy to revise, rebase, or close this if it's not a fit for your project.

Quick update since I opened it: Cardano docs shipped the plugin (merged in input-output-hk/cardano-documentation#739), so it's now running in production on Ethereum execution-apis, Sui (Mysten Labs), Walrus, Seal, SuiNS, Monad, Flare, Kaia, Nillion, Chronicle, and Cardano. Also now listed in the official Docusaurus community plugins.

No worries if this isn't on your roadmap — just want to make sure it didn't slip through the cracks.

[portdeveloper]

fyi shipped 0.5.2 today and pushed the version bump (^0.4.2 → ^0.5.2) on this branch.

the most relevant fix: the button now renders on pages without a ToC. previously the fallback was a fixed-position overlay in the top-right viewport corner which often got hidden behind navbars — easy to miss when reviewing a landing/index page. now it injects inline after the breadcrumbs.

also in 0.5.2: button + dropdown inherit --ifm-font-family-base (was browser default), min-height reserved on the container to reduce layout shift, and a MutationObserver replaces the chained setTimeout polling so the button shows up reliably on first render.

all credit to @Simek who reviewed facebook/react-native-website#5085 and flagged these.

happy to close this out if not a fit — just wanted to flag the fixes in case the no-ToC behavior was a blocker.