RTC does not sync linked entities (global styles, templates) to collaborators

[pavel-mailpoet]

Description

When two users are collaboratively editing a post, RTC correctly syncs post content changes in real time via /wp-sync/v1/updates. However, changes to linked entities — specifically wp_global_styles and wp_template posts — are not synced to other collaborators.

Steps to reproduce

1. Open the same post in two browser sessions (two different users)
2. User A changes a global style (e.g., font family or color) via the Styles sidebar
3. User B's editor does not reflect the style change — they still see the old styles

Same applies to template content: if User A edits the template (header/footer), User B doesn't see the update.

Why this matters

Global styles and templates are stored as separate posts (wp_global_styles, wp_template). RTC only syncs the post being edited, not related posts. For extenders building custom editors on top of Gutenberg (e.g., WooCommerce email editor), this means the collaborative editing experience is incomplete — content syncs but styles and templates don't.

Expected behavior

When a collaborator changes a global style or template that affects the post being edited, other collaborators should see the updated styles/template in their editor.

Environment

WordPress 7.0 Beta 6