Cleaned up unnecessary System.Net and System.Net.Http.Json usings across multiple files, including controllers and API client classes, to reduce dependencies and improve code clarity.
Refactored error handling logic for API responses into a new static ApiClientHelper class, consolidating the ReadErrorAsync method and ProblemDetailsDto. Updated CatalogApiClient and MassDataApiClient to use the shared helper, removing redundant local methods and classes. This change improves consistency, reduces duplication, and streamlines error message formatting across the application.