tensorflow/playground ? reverse-engineered prompt

Build me an interactive web app where I can play with a simple neural network and see how it behaves in real time.

I want a clean page that shows the network visually, lets me change the setup and training inputs, and updates the chart and decision boundary live as I experiment. It should feel like a learning tool, so the visuals need to be easy to understand and responsive when I tweak things.

Please make it work as a small TypeScript app with polished styling and smooth D3 based animations or transitions if that fits. I also want it to be easy to run locally, build for production, and serve from a browser without extra fuss. If you need to check current docs or best practices for anything, go ahead and look them up online.