Clean up and organize using statements across files

Removed unused and redundant using/import statements from multiple files, including command, repository, and Program.cs. No functional changes; this commit improves code clarity and organization.

DbFirst.Application/Catalogs/Commands/CreateCatalogCommand.cs

@@ -1,4 +1,3 @@
-using DbFirst.Application.Catalogs;
 using MediatR;
 
 namespace DbFirst.Application.Catalogs.Commands;

DbFirst.Application/Catalogs/Commands/UpdateCatalogCommand.cs

@@ -1,4 +1,3 @@
-using DbFirst.Application.Catalogs;
 using MediatR;
 
 namespace DbFirst.Application.Catalogs.Commands;

DbFirst.Application/Catalogs/Queries/GetAllCatalogsQuery.cs

@@ -1,4 +1,3 @@
-using DbFirst.Application.Catalogs;
 using MediatR;
 
 namespace DbFirst.Application.Catalogs.Queries;

DbFirst.Application/Catalogs/Queries/GetCatalogByIdQuery.cs

@@ -1,4 +1,3 @@
-using DbFirst.Application.Catalogs;
 using MediatR;
 
 namespace DbFirst.Application.Catalogs.Queries;