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.Api/Hubs/StatusHub.cs

@@ -1,4 +1,4 @@
-using JdeScoping.Core.ApiContracts.SignalR;
+using JdeScoping.Core.ViewModels;
 using Microsoft.AspNetCore.SignalR;
 using Microsoft.Extensions.Logging;
 
@@ -9,7 +9,7 @@ namespace JdeScoping.Api.Hubs;
 /// </summary>
 public class StatusHub : Hub
 {
-    private static StatusUpdateDto _cachedStatus = new()
+    private static StatusUpdateViewModel _cachedStatus = new()
     {
         Message = "Unknown",
         Timestamp = DateTime.UtcNow
@@ -27,7 +27,7 @@ public class StatusHub : Hub
     /// Caches the update and broadcasts to all clients.
     /// </summary>
     /// <param name="statusUpdate">Status update to broadcast</param>
-    public async Task SetStatus(StatusUpdateDto statusUpdate)
+    public async Task SetStatus(StatusUpdateViewModel statusUpdate)
     {
         _cachedStatus = statusUpdate;
         await Clients.All.SendAsync("statusUpdate", statusUpdate);
@@ -38,7 +38,7 @@ public class StatusHub : Hub
     /// Called by clients to get initial cached status on connection.
     /// </summary>
     /// <returns>The most recent status update</returns>
-    public StatusUpdateDto GetCachedStatus()
+    public StatusUpdateViewModel GetCachedStatus()
     {
         return _cachedStatus;
     }
@@ -47,7 +47,7 @@ public class StatusHub : Hub
     /// Called by controllers/services to broadcast search updates.
     /// </summary>
     /// <param name="searchUpdate">Search update to broadcast</param>
-    public async Task PublishSearchUpdate(SearchUpdateDto searchUpdate)
+    public async Task PublishSearchUpdate(SearchUpdateViewModel searchUpdate)
     {
         await Clients.All.SendAsync("searchUpdate", searchUpdate);
         _logger.LogDebug("Search update published: ID={Id}, Status={Status}", searchUpdate.Id, searchUpdate.Status);