Decide the collinear magnetic ground state by comparing total energies across enumerated orderings, one SCF each at identical settings. Returns the ground-state ordering (FM / AFM / ferrimagnetic), its net moment and Ms, and the energy margin over the next ordering. Use this rather than reading the sign of site moments from a single SCF: a seeded SCF shows a configuration is stable, not that it is preferred. Supercells are generated when the input cell cannot host an ordering. Costs one SCF per configuration, so screen with cheaper routes first.