[FEA] Switch from mypy to ty

**Is your feature request related to a problem? Please describe.**
The astral team have announced [ty](https://github.com/astral-sh/ty), a Rust-based Python type checker that provides substantial speedups over mypy. mypy runs fairly slowly on our code base and is especially noticeable for pre-commit checks, so switching would be beneficial.

**Describe the solution you'd like**
`ty` is still very new and likely not yet stable enough to be worth using. We should revisit the possibility once they put out at least a 0.1 version (right now they are still on alphas only).