Add "Multiplayer Drawing" Example

[Jei-sKappa]

First of all, thank you for the amazing work on this package! 🥳
This PR adds a "Multiplayer Drawing" example.

Key consideration:

When running the example, you'll notice that the number of offline writes increases rapidly as you move the pointer and draw.
From what I understand (unless I’m missing something 😅), this may be due to the lack of a concept like "awareness" (as implemented in Yjs), which would help manage presence/state without generating CRDT changes for every pointer move.

I'd love to hear your thoughts on this. Thanks again!

[MattiaPispisa]

Thanks for the compliments and for adding another example!

At the moment, there isn’t yet an “awareness”-like concept similar to what Yjs offers, but it’s definitely something that needs to be integrated.
This concept doesn’t directly relate to the data being collaboratively edited, so it shouldn’t be saved as a Change. Instead, it should act more like a “plugin” that attaches to the document.

Right now, I’m working on creating the sync package, which is a key building block for providing a plug-and-play system to manage CRDT data. This will also lay the groundwork for integrating awareness.