Reworks the editor playground into a tabbed showcase:
- Rich text & blocks: drag-to-reorder handles, bubble/slash menus, and a live output panel (block/word counts, selection readout, document JSON).
- Multiplayer: two CRDT replicas synced over an in-memory channel with remote cursors, an in-sync indicator, and a Connected/Offline toggle that demonstrates divergence → convergence.
Also removes the focus outline on the contenteditable (outline: none on the editable surface).
A live @robonen/editor instance (default registry) as a doc section at /editor/playground: a reactive formatting toolbar, the bubble/slash menus, and a sample document exercising every block and mark — styled with the docs design tokens and wrapped in <ClientOnly> for SSR. Links it from the editor intro.
robonen