refactor(core): reorganize DTOs into Models and ViewModels folders

Move DTOs from ApiContracts to appropriate locations:
- SignalR DTOs → ViewModels (renamed Dto→ViewModel suffix)
- Pipeline DTOs → Models/Pipelines
- UserInfoDto → Models/Auth
- DataUpdateDto → Models/Infrastructure

NEW/src/JdeScoping.Client/Auth/UserStorageService.cs

@@ -1,5 +1,5 @@
 using System.Text.Json;
-using JdeScoping.Core.ApiContracts.Auth;
+using JdeScoping.Core.Models.Auth;
 using Microsoft.JSInterop;
 
 namespace JdeScoping.Client.Auth;