Well done. We are building something similar [1] and found that generating UIs (mostly charts) on the fly works surprisingly well in most cases, but can be a bit frustrating if you know exactly what you want and just can't prompt it (as a user) to do that because of some edge case.
While this is a cool demo that shows what LLMs can do I am a bit surprised how polished and advanced it looks (even PDF upload) for a quick start. Anyway I love that it's open source so we can learn from it.