Setup yjs dependency

[heavyweight]

Fixes #

Proposed changes:

• Ensure same instance of Yjs

Other information:

• Have you written new tests for your changes, if applicable?
• Have you checked the E2E test CI results, and verified that your changes do not break them?
• Have you tested your changes on WordPress.com, if applicable (if so, you'll see a generated comment below with a script to run)?

Jetpack product discussion

Does this pull request change what data or activity we track or use?

Testing instructions:

• Sync the PR changes to your site
• Sync the latest version of gutenberg
• Apply this to gutenberg-rtc.ts

import { addFilter } from '@wordpress/hooks';
import { Y } from '@wordpress/sync';

const win = window as unknown as { wp?: { sync?: { Y?: unknown } } };
if ( win.wp?.sync?.Y ) {
	// eslint-disable-next-line no-console
	console.assert( Y === win.wp.sync.Y, 'ERROR: Two Yjs instances detected!' );
	// eslint-disable-next-line no-console
	console.log( 'Yjs instance check passed:', Y === win.wp.sync.Y );
} else {
	// eslint-disable-next-line no-console
	console.error( 'Yjs instance not found!' );
}

// Register PingHub provider and disable Http polling by returning only this provider.
( function register() {
	if ( typeof window === 'undefined' ) {
		return;
	}
	addFilter( 'sync.providers', 'wpcom/pinghub-provider', () => [] );
} )();

• The instance check should pass

Changelog

• Generate changelog entries for this PR (using AI).

[github-actions]

Are you an Automattician? Please test your changes on all WordPress.com environments to help mitigate accidental explosions.

• To test on WoA, go to the Plugins menu on a WoA dev site. Click on the "Upload" button and follow the upgrade flow to be able to upload, install, and activate the Jetpack Beta plugin. Once the plugin is active, go to Jetpack > Jetpack Beta, select your plugin (Jetpack or WordPress.com Site Helper), and enable the DOTCOM-16099 branch.
• To test on Simple, run the following command on your sandbox:

bin/jetpack-downloader test jetpack DOTCOM-16099

bin/jetpack-downloader test jetpack-mu-wpcom-plugin DOTCOM-16099

Interested in more tips and information?

• In your local development environment, use the jetpack rsync command to sync your changes to a WoA dev blog.
• Read more about our development workflow here: PCYsg-eg0-p2
• Figure out when your changes will be shipped to customers here: PCYsg-eg5-p2

[github-actions]

Thank you for your PR!

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Code Coverage Summary

This PR did not change code coverage!

That could be good or bad, depending on the situation. Everything covered before, and still is? Great! Nothing was covered before? Not so great. 🤷

Full summary · PHP report · JS report

[Copilot]

Pull request overview

This PR configures Yjs dependency management to ensure a single instance is used across the application, preventing conflicts with shared document types. The change addresses the known Yjs issue where multiple instances break shared document functionality.

Changes:

• Added @wordpress/sync, yjs, lib0, and y-protocols as dependencies
• Configured webpack externals to map both @wordpress/sync and yjs to WordPress globals
• Converted gutenberg-rtc entry point from .js to .ts

Reviewed changes

Copilot reviewed 2 out of 4 changed files in this pull request and generated no comments.

File	Description
projects/packages/jetpack-mu-wpcom/webpack.config.js	Added webpack externals configuration to resolve @wordpress/sync and yjs to WordPress globals, updated entry point file extension
projects/packages/jetpack-mu-wpcom/package.json	Added @wordpress/sync, yjs, lib0, and y-protocols package dependencies

Files not reviewed (1)

• pnpm-lock.yaml: Language not supported

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