Initial reproducible benchmark release

First versioned release of the IrO2 quantum Hamiltonian extraction workflow. This release tags the pipeline in the state used to generate benchmark datasets reported in the associated preprint (doi:10.5281/zenodo.19491027, under review at Nature, 2026). The main branch contains stable, tested reference scripts and documentation. The full end-to-end pipeline including active-space selection and Hamiltonian reduction is being developed in a separate branch.