Migrate Python bindings to Nanobind.

[psobot]

Tests still pass.

Still need to ensure that CI/CD works as expected, resulting wheels are smaller, and - most importantly - that docstring generation and type hint generation work without my absolutely awful hack of a script.

• My code follows the code style of this project.
• I have added and/or updated appropriate documentation (if applicable).
• All new and existing tests pass locally with these changes.
• I have run static code analysis (if available) and resolved any issues.
• I have considered backward compatibility (if applicable).
• I have confirmed that this PR does not introduce any security vulnerabilities.

[markkohdev]

👍 Nice! Nice to see a lot of the pybind fluff go away. Ruff also seems like a solid choice as well :)

[stephen29xie]

I was able to build locally with this new setup 👍. The migration in the Python bindings contains a breaking change though.

Some places to clean up:

• Update CONTRIBUTING.md
  • the Building Python section contains a reference to the removed setup.py
  • The Troubleshooting section contains a reference to pybind11
• python/dev-requirements.txt contains pybind11 and pybind11-stubgen