Upgrade Geant4 to 11.4.3 (#103)

Geant4 11.4.3 with its datasets (incl. the new G4CHANNELING); reuse of datasets downloaded for another Geant4 version; installed-Geant4 datasets found via env vars / geant4-config --check-datasets; a clear error instead of a crash for primaries outside the world; example, notebook and test gun positions moved inside their worlds; Build and Test runs every example port.

Install into a fresh virtual environment; show both authors on PyPI (#…

…101)

README and INSTALLATION.md start with creating a venv or a new conda env. Authors and maintainers listed by name so PyPI shows both. README badges for downloads and views.

Fix the Binder badges and link the PyPI page from the README (#100)

Binder badges open examples/attenuation.ipynb and install the published package from PyPI (binder/requirements.txt). The installation section links the PyPI project page.

One-click install: macOS and Linux wheels with a pip-installable Qt v…

…iewer (#98)

Prebuilt wheels for macOS (arm64, x86_64) and Linux x86_64, Python 3.8-3.13, bundle Geant4 11.2.2. An optional [gui] extra installs Qt from PyQt5-Qt5 for a viewer module that only Application.visualize() loads. Also: resumable, verified dataset downloads; an extended Python API; ported Geant4 examples; licence notices for the bundled libraries; rewritten installation docs.

build wheels for python 3.12

update README.md