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.Core/Models/Auth/LoginResultModel.cs

@@ -1,5 +1,3 @@
-using JdeScoping.Core.ApiContracts.Auth;
-
 namespace JdeScoping.Core.Models.Auth;
 
 /// <summary>

NEW/src/JdeScoping.Core/Models/Auth/UserInfoDto.cs

@@ -0,0 +1,52 @@
+namespace JdeScoping.Core.Models.Auth;
+
+/// <summary>
+/// API response DTO for authenticated user information.
+/// </summary>
+public record UserInfoDto
+{
+    /// <summary>
+    /// User's login username.
+    /// </summary>
+    public string Username { get; init; } = string.Empty;
+
+    /// <summary>
+    /// User's first name.
+    /// </summary>
+    public string FirstName { get; init; } = string.Empty;
+
+    /// <summary>
+    /// User's last name.
+    /// </summary>
+    public string LastName { get; init; } = string.Empty;
+
+    /// <summary>
+    /// User's display name (computed on server).
+    /// </summary>
+    public string DisplayName { get; init; } = string.Empty;
+
+    /// <summary>
+    /// User's organization title.
+    /// </summary>
+    public string Title { get; init; } = string.Empty;
+
+    /// <summary>
+    /// User's email address.
+    /// </summary>
+    public string EmailAddress { get; init; } = string.Empty;
+
+    /// <summary>
+    /// Creates a UserInfoDto from a UserInfo entity.
+    /// </summary>
+    /// <param name="userInfo">The UserInfo entity to convert.</param>
+    /// <returns>A new UserInfoDto instance.</returns>
+    public static UserInfoDto FromUserInfo(UserInfo userInfo) => new()
+    {
+        Username = userInfo.Username,
+        FirstName = userInfo.FirstName,
+        LastName = userInfo.LastName,
+        DisplayName = userInfo.DisplayName,
+        Title = userInfo.Title,
+        EmailAddress = userInfo.EmailAddress
+    };
+}