nest-service

Implements the service layer of a use case (UC-XXX) in a NestJS application: @Injectable service classes in the feature folder, the business rules with UC-XXX BR-YYY markers, domain errors for every rejection the API or UI turns into a message, and writes that span repositories in one transaction through the repository. Calls the persistence layer only through the repository its Handover names, imports no Drizzle and no HTTP type, and detects the API app root and ESM/NodeNext, where every relative import ends in .js. Use when the user asks to "implement the service layer", "write the business logic", "enforce the business rules", "create a NestJS service", or mentions providers, @Injectable services, domain errors, or a feature module's service in a project that combines layer plugins. Normally run by /use-case-implement after the persistence layer; it can also be run directly. The controller is /nest-rest.