You can't.

Mobile application require strange wrappings and packagings to run native code like that.

On android you could potentially use termux and build from source for aarch64, but iOS doesn't have anything like that.

Furthermore, iOS is very locked down, so running some random source from GitHub is essentially impossible without proper developer tools and a mac to run them.

I used to write C++ and compile + run it on a jailbroken iPhone. It worked fine but obviously had no access to most of the Apple hardware, interfaces, or anything else.

Can iOS even run rust applications? What is the repo?

Apple:

Youd have to bridge it into swift or objective c using the c interop system and then then manually invoke main.