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

[amotl]

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

Using uv build creates a wheel package without any code. (8200dfe)

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 #786 (comment)

[amotl]

Thank you for bringing this up.

Isn't this an indication that there's something wrong [...]

Absolutely. I was equally confused, but it happened like described on my machine (uv 0.9.18, Hatch 1.16.2): The source package tarball was populated properly, but the wheel package included no code just package metadata. Let's try it again, possibly investigate why that happens, and report about it properly, or fix the Hatch configuration.