Validate packaging configuration: `uv build` vs. `hatch build`

Sorry to nitpick further here, but I'm a bit confused about this change:

> Using `uv build` creates a wheel package without any code. (8200dfeb14818e9dbbc37737aef67cb7f33ad22b)

Isn't this an indication that there's something wrong with the pyproject.toml definition? `uv build` acts as a build frontend, using the build backend defined in `[build-system]`. So `uv build` should actually install & use hatch itself.

_Originally posted by @mfussenegger in https://github.com/crate/crate-python/issues/786#issuecomment-3996743867_