- Add nuclear_data.py module for paceENSDF integration and JSON input
- Add DecayInfo and BranchInfo dataclasses for parsed nuclear data
- Implement get_decay_info_from_paceENSDF() to retrieve decay parameters
- Implement load_json_input() and json_to_config() for custom JSON input
- Add create_config_from_source() unified interface for both sources
- Add bs_pnpi CLI with --nuclide, --input, --output, --plot, and detector options
- Add 23 comprehensive tests for nuclear_data module
- Add sample JSON input file
- Update __init__.py and pyproject.toml with new exports and entry point
- Add paceENSDF as optional dependency
unzhakov
1269244b93