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/src/JdeScoping.DataSync/Configuration/MergeConfigurations/JdeUserMergeConfiguration.cs

@@ -0,0 +1,24 @@
+using System.Linq.Expressions;
+using JdeScoping.Core.Models.Organization;
+using JdeScoping.DataSync.Contracts;
+
+namespace JdeScoping.DataSync.Configuration.MergeConfigurations;
+
+/// <summary>
+/// Merge configuration for JdeUser entities.
+/// </summary>
+public sealed class JdeUserMergeConfiguration : IMergeConfiguration<JdeUser>
+{
+    public string TableName => "JdeUser";
+
+    public Expression<Func<JdeUser, object>> MatchOn =>
+        x => x.AddressNumber;
+
+    public Expression<Func<JdeUser, object>>? UpdateColumns =>
+        x => new { x.UserId, x.FullName };
+
+    public Expression<Func<JdeUser, JdeUser, bool>>? UpdateWhen =>
+        (src, tgt) => src.LastUpdateDt > tgt.LastUpdateDt;
+
+    public Expression<Func<JdeUser, object>>? InsertColumns => null;
+}