toeverything/blocksuite ? reverse-engineered prompt

Build me a web based block editor toolkit that I can use to make collaborative apps, with a clean demo I can open in the browser.

I want the core to support editable blocks, rich text inside blocks, custom embeds, and real time collaboration so two people can edit the same document at once. It should also let me reuse the same document in more than one editor view, and save and load content reliably. If it helps, include a couple of example editors, one for a normal page style document and one more freeform canvas style view.

Make the components work as native web components so they can be used in different frameworks later. Please also include a simple getting started example, a few useful docs, and make sure the project runs cleanly from a fresh install. If you need to check current library docs or best practices online, go ahead.