refactor: remove unused classes and consolidate ViewModels in Core

Remove 9 unused types from Core (duplicate extension classes, TableSpec, ColumnSpec, LotLocation), move ComponentLotViewModel and OperatorViewModel from Client to Core, and refactor DataSync.Dev to use pipeline-based configuration. Fix Login.razor to use UserInfoDto directly.

NEW/tests/JdeScoping.Api.Tests/Hubs/StatusHubTests.cs

@@ -1,8 +1,5 @@
 using JdeScoping.Api.Hubs;
-using JdeScoping.Core.Models;
-using JdeScoping.Core.Models.Enums;
-using JdeScoping.Core.Models.Infrastructure;
-using JdeScoping.Core.Models.Search;
+using JdeScoping.Core.ApiContracts.SignalR;
 using Microsoft.AspNetCore.SignalR;
 using Microsoft.Extensions.Logging;
 using NSubstitute;
@@ -36,7 +33,7 @@ public class StatusHubTests
         var clientsProperty = typeof(Hub).GetProperty("Clients");
         clientsProperty?.SetValue(_hub, hubClients);
 
-        var statusUpdate = new StatusUpdate
+        var statusUpdate = new StatusUpdateDto
         {
             Message = "Processing",
             Timestamp = DateTime.UtcNow
@@ -93,13 +90,12 @@ public class StatusHubTests
         var clientsProperty = typeof(Hub).GetProperty("Clients");
         clientsProperty?.SetValue(_hub, hubClients);
 
-        var searchUpdate = new SearchUpdate
+        var searchUpdate = new SearchUpdateDto
         {
             Id = 42,
             UserName = "testuser",
             Name = "Test Search",
-            Status = SearchStatus.Running,
-            Timestamp = DateTime.UtcNow
+            Status = "Running"
         };
 
         // Act