ethereum-lists/4bytes — reverse-engineered prompt

Build me a simple Ethereum signature lookup tool based on this repo. I want to be able to paste in a 4 byte hex selector like a9059cbb and instantly see the human readable function name or names that match it, like transfer(address,uint256). If there are multiple matches, show all of them clearly instead of hiding collisions. If the repo also has versions with parameter names, show those too when available.

It would also be great if I could do the reverse and search by a function signature to find its selector. Keep the experience friendly for someone inspecting contract calldata, with clear empty states for unknown selectors and a copy button for results. Use the data in this repository as the source of truth, and make it easy to refresh the local data later.

Please include a small README with how to run it and a couple example lookups. Keep the setup straightforward. If you need to, look up current docs online.