Use uv to run CI

[adenzler-nvidia]

This PR changes the CI to use the dependency versions locked in the uv.lock file. Right now CI tests against latest dev version of warp and mujoco, which means the uv workflow is untested and we have no test for known-good dependencies.

I made this a draft because there's definitely a discussion to be had here. My stance is that we should have nightlies for dev versions of mujoco/warp and use the uv workflow for the package that ships/users will use. Like this, any change that needs a change in minimum versions should be including a version upgrade as well, and we explicitly know when we are breaking dependencies.

But I probably don't have the full picture here, so let's discuss.

[thowell]

thanks @adenzler-nvidia!
#917 is probably relevant to this discussion

[adenzler-nvidia]

yes, looks super relevant. Not sure if everything on this matrix needs to be tested on each PR, I think for forward compatibility it's ok to have nightlies (for uv-locked mujoco + nightly warp, or uv-locked warp and nightly mujoco).

[adenzler-nvidia]

The other thing we need (which I didn't include but we probably should) is to make sure pyproject.toml specifies correct min version that actually work. For example, the warp-lang requirement of >= 1.9.0 likely doesn't work.