[Feature] Sophia Optimizer

[namgyu-youn]

Hi there, i am Youn from South Korea. I have been used HeavyBall, and thought this project is interesting.
After reading the source code, i want to contribute to this project.

I want to introduce Sophia Optimizer. (See also : ArXiv, Implemented Codebase)

Before the start, i want to hear your opinion about this. Is there something should i care? (btw, I love Ruff)

[ClashLuke]

Hi Youn, your Sophia implementation looks great! I'd love to add it to HeavyBall.
I've added a few comments to your commit. Feel free to open a PR :)