ACTIVATE when creating or modifying frontend features in projects with domain/infrastructure layered architecture. ACTIVATE for 'frontend architecture', 'domain layer', 'hexagonal frontend', 'features/ folder', 'repository interface', 'mapper'. Covers: features/{feature-name}/domain + infrastructure structure, strict dependency direction (domain never imports infrastructure), domain models/repositories/services/referentials, API repositories, mappers, hooks as orchestrators. DO NOT use for: projects without this architecture (ask user first), general React patterns (see frontend-component-patterns).
