عرض عملي: CRUD كامل للفئات، مباشرةً

خطوة بخطوة

1. Create CategoryController with a record DTO for create and update, using the in-memory repository.
2. Implement POST (201 plus Location) and GET by ID and list.
3. Implement PUT and DELETE (204).
4. Planned mistake: the GET for an unknown ID returns 200 with an empty body. Fix: throw a not-found error so the client gets 404.
5. Call every endpoint with curl -i, then add a @WebMvcTest for each.