Assistant can't edit Yjs doc

1. Open a doc
2. Open assistant, ask it to make some eidts
3. It can't read the yjs text

I think it may need some adjusted helper functions. 

<img width="1749" height="1124" alt="Image" src="https://github.com/user-attachments/assets/e0f53ca6-29ba-4d12-9d13-af509e00a8e7" />
