fix native wheel platform tag

[rahulsiiitm]

Summary

• declare setuptools as the PEP 517 build backend
• mark the distribution as containing native extensions so wheels receive a platform-specific tag
• build and install the wheel in CI, including an explicit guard against none-any wheels

Why

msgq packages pre-built Cython shared objects. Without telling setuptools that the distribution contains native extensions, the generated wheel can be tagged as platform-independent even though its binaries only work on the OS and architecture that built them.

Test plan

• pip wheel . --no-deps --no-build-isolation produces msgq-0.0.1-cp312-cp312-win_amd64.whl
• bash -n test.sh setup.sh
• git diff --check
• CI builds and imports the installed wheel on Ubuntu and macOS

Related to #619.