Function score_contract 

pub fn score_contract(
    contract: &Contract,
    binding: Option<&BindingRegistry>,
    stem: &str,
) -> ContractScore

Score a single contract against its completeness and verification depth.

Five dimensions (weights from spec):

• D1: Specification depth (20%)
• D2: Falsification coverage (25%)
• D3: Kani proof coverage (25%)
• D4: Lean proof coverage (10%)
• D5: Binding coverage (20%)