Initial commit: JDE Scoping Tool migration project

Set up repository with legacy .NET Framework 4.8 source (OLD/),
new .NET 10 Blazor solution (NEW/), OpenSpec specifications,
documentation, and project configuration.

NEW/tests/JdeScoping.DataSync.IntegrationTests/Infrastructure/BulkMergeTestEntity.cs

@@ -0,0 +1,12 @@
+namespace JdeScoping.DataSync.IntegrationTests.Infrastructure;
+
+/// <summary>
+/// Test entity for BulkMergeHelper integration tests.
+/// </summary>
+public class BulkMergeTestEntity
+{
+    public int Id { get; set; }
+    public string Name { get; set; } = string.Empty;
+    public decimal? Amount { get; set; }
+    public DateTime LastUpdateDt { get; set; }
+}