Convert Python bindings to declarative PyO3 module syntax

[kilian-hu]

Description

This PR converts the Python bindings from the old function-based #[pymodule] style to the new and recommended declarative style.

Also updating uv.lock which I forgot to do in #6103

Motivation and context

• The declarative style is less verbose and easier to read
• As seen in Declarative modules next steps PyO3/pyo3#3900 declarative modules will be the recommended way of using PyO3 and function-based modules are going to be deprecated, quote:

  Before v0.23 (or later?):

  • Deprecate #[pyfn]
  • Deprecate "function-based" modules

• Another quote from one of the PyO3 maintainers Declarative modules next steps PyO3/pyo3#3900 (comment)

  I agree that imperative modules should be deprecated and replaced with these modules as soon as possible.

• The docs have also been rewritten to use the declarative style, see Guide: focus on the module way of creating python modules PyO3/pyo3#5430
• Declarative modules are better supported by experimental-inspect (Next steps for type introspection and stub generation PyO3/pyo3#5137) which I'd like to attempt using in a future PR for type stub generation.

Description of AI Usage

I've used Claude Code with Opus 4.6 to search through the PyO3 docs and various GitHub issues and PRs to validate the idea and to make the code changes to bindings/python/src/lib.rs.

[turso-bot]

Please review @LeMikaelF