binding `hb_gpu`?

Hey once more,

I am really excited about the new possibilities with glyph rendering and wanted to try setting up a demo for wgpu-py. If I read the source correctly, `uharfbuzz` only exposes a subset of the harfbuzz library. I am not sure how complex the cython bindings are to setup(some one other issue disussing it) or how useful this is for other python users.

My goal is to access the shader source as well as the draw buffer, so it can be bound and run in wgpu-py for downstream use e.g. https://github.com/pygfx/pygfx/issues/391#issuecomment-4286896991
It also seems that the API is still developing, so perhaps it's not a good idea to bind experimental parts?

Let me know if this is an effort worth trying and I might find a bit of time to attempt it.