Refactored DTO class and namespace names from Massdata* to MassData* in DbFirst.Contracts. Updated all relevant application files to use the correct DTO namespaces for Catalogs and MassData. Adjusted _Imports.razor to include new DTO namespaces and removed unused usings. These changes improve code consistency and reduce namespace-related errors.
Replaced direct service usage in CatalogsController with MediatR-based commands and queries for all CRUD operations. Added command/query and handler classes for Catalog operations. Updated dependency injection to register MediatR and removed ICatalogService. Improved code maintainability and testability by adopting CQRS architecture.