Ln 643 Api Contract Auditor

Audits API contracts at service boundaries by checking for layer leakage (HTTP types in service methods), missing DTOs, entity leakage to APIs, inconsistent error handling, and redundant overloads. Works in global or domain-aware mode, uses two-layer detection with language-specific grep patterns, and scores compliance, completeness, quality, and implementation separately. The findings focus purely on architecture boundaries, not code duplication or internal implementation details. Each issue gets tagged with an action like ADD_DTO or STOP_ENTITY_LEAK. Useful when you need to verify clean separation between API, service, and domain layers, especially in codebases where request objects have started bleeding into business logic.