chore: update GitHub username references (yehudalevy-collab -> ymxlx)

Author: ymxlx

README.md

@@ -3,7 +3,7 @@
 ![TypeScript](https://img.shields.io/badge/TypeScript-5.8-3178c6)
 ![three.js](https://img.shields.io/badge/three.js-r184-000000)
 ![React 19](https://img.shields.io/badge/React-19-61dafb)
-[![CI](https://github.com/yehudalevy-collab/proofs-of-nine/actions/workflows/ci.yml/badge.svg)](https://github.com/yehudalevy-collab/proofs-of-nine/actions/workflows/ci.yml)
+[![CI](https://github.com/ymxlx/proofs-of-nine/actions/workflows/ci.yml/badge.svg)](https://github.com/ymxlx/proofs-of-nine/actions/workflows/ci.yml)
 
 The number **9**, written by itself in infinite mathematics.