Introduce DTOs and refactor app layer to use them

Added DTO classes for Connection, Endpoint, EndpointAuth, EndpointParam, Profile, and RecAction. Updated AutoMapper profiles, DbContext, and command handlers to use DTOs instead of domain entities. This decouples the application layer from the domain model, improving maintainability and flexibility. Cleaned up some using directives and file headers.

src/ReC.Application/RecActions/Commands/DeleteRecActionsCommand.cs

@@ -11,7 +11,7 @@ public class DeleteRecActionsCommand : IRequest
     public required long ProfileId { get; init; }
 }
 
-public class DeleteRecActionsCommandHandler(IRepository<RecAction> repo) : IRequestHandler<DeleteRecActionsCommand>
+public class DeleteRecActionsCommandHandler(IRepository<RecActionDto> repo) : IRequestHandler<DeleteRecActionsCommand>
 {
     public async Task Handle(DeleteRecActionsCommand request, CancellationToken cancel)
     {