[Feature]: Please add import PDF feature to the tldraw.com website
### What's the feature?

Teachers who use whiteboard apps and websites require to import their notes and materials as PDFs in the whiteboard to teach their students online. But tldraw has no PDF feature it only supports image importing.
So we need to add this feature which includes two things:
1. Selecting a PDF and opening one of it page which the user will select.
2. The pages should be turned left and right using arrow keys. Navigation between different pages should be easy

There is an app "Openboard" which has this feature but, the UI of tldraw is far better than openboard. 
So I will recommend tldraw to my father who is a teacher once this feature gets added. Thank You!

Here are the screenshots of openboard pdf feature.

![Image](https://github.com/user-attachments/assets/c58e4170-ef91-4779-bfb0-afe919cae28e)
![Image](https://github.com/user-attachments/assets/aeda1707-f6ea-4a5c-93ae-f359ac32faba)

### Where would you like this feature?

The tldraw.com website

### Contact Details

fbyogesh111@gmail.com

### Code of Conduct

- [x] I agree to follow this project's Code of Conduct