feat(D.2b): factory propagates ReadOrder→ZOrder for faithful draw layering

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

src/AcDream.App/UI/Layout/DatWidgetFactory.cs

@@ -63,6 +63,9 @@ public static class DatWidgetFactory
         e.Width  = info.Width;
         e.Height = info.Height;
 
+        // Honor the dat's draw order so overlapping pieces (grip overlay over bevel chrome) layer correctly.
+        e.ZOrder = (int)info.ReadOrder;
+
         // Map the four raw edge-anchor values to the AnchorEdges bit-flag that the
         // UI layout engine uses for reflow.
         e.Anchors = ElementReader.ToAnchors(info.Left, info.Top, info.Right, info.Bottom);