Function check_foundation_models 

pub fn check_foundation_models(
    register: &FoundationRegister,
) -> Vec<FoundationProblem>

Checks that a register keeps foundations neutral.

Every model belongs to a declared family, distinct models are not merged or claimed equal, every correspondence states its condition, every language names its own models, and no model is a universal logic. Unknown fields such as universal are rejected when the register is parsed. An empty result means the register is neutral; the kinds match the JavaScript runtime’s checkFoundationModels.