fix(build): enable python-bindings feature in maturin config

- Add python-bindings feature to maturin build configuration
- Ensures PyO3 extension module is built correctly for PyPI
- Fixes PyInit__core symbol warning during wheel build

This is required because we removed python-bindings from default features
to fix cargo publish linking issues. Maturin now explicitly enables it.

pyproject.toml

@@ -56,7 +56,7 @@ Issues = "https://github.com/ThotDjehuty/optimiz-r/issues"
 [tool.maturin]
 python-source = "python"
 module-name = "optimizr._core"
-features = ["pyo3/extension-module"]
+features = ["python-bindings"]
 
 [tool.pytest.ini_options]
 testpaths = ["tests"]