Here's the first version: zkvisualizer.com
It walks through the full pipeline step by step (Problem → Circuit → R1CS → Polynomials → Witness → Proof → Verification) with real Groth16 proofs generated in your browser using snarkjs.
You can toggle between what the prover knows vs what the verifier sees, and there's a tamper detection demo where you can watch verification fail.
This is still very early on, but I would be very happy to receive any feedback!