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.Core/Models/AuthResult.cs

@@ -0,0 +1,12 @@
+namespace JdeScoping.Core.Models;
+
+/// <summary>
+/// Result of an authentication attempt
+/// </summary>
+/// <param name="Success">Whether authentication was successful</param>
+/// <param name="User">User info if successful, null otherwise</param>
+/// <param name="ErrorMessage">Error message if failed, null otherwise</param>
+public record AuthResult(
+    bool Success,
+    UserInfo? User,
+    string? ErrorMessage);