fix: sync TemplateRegionOverlayCanvas sizing with RectanglesCanvas

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

Author: TheJoeFin

Text-Grab/Views/GrabFrame.xaml

@@ -573,6 +573,7 @@
                                 </Canvas>
                                 <Canvas
                                     x:Name="TemplateRegionOverlayCanvas"
+                                    Margin="-4,-2,0,0"
                                     Panel.ZIndex="5"
                                     ClipToBounds="True"
                                     IsHitTestVisible="False" />

Text-Grab/Views/GrabFrame.xaml.cs

@@ -1771,12 +1771,14 @@ private void SyncRectanglesCanvasSizeToImage()
         {
             GrabFrameImage.Width = sourceWidth;
             RectanglesCanvas.Width = sourceWidth;
+            TemplateRegionOverlayCanvas.Width = sourceWidth;
         }
 
         if (double.IsFinite(sourceHeight) && sourceHeight > 0)
         {
             GrabFrameImage.Height = sourceHeight;
             RectanglesCanvas.Height = sourceHeight;
+            TemplateRegionOverlayCanvas.Height = sourceHeight;
         }
     }
 
@@ -2723,6 +2725,8 @@ private void ResetGrabFrame()
         RectanglesCanvas.RenderTransform = Transform.Identity;
         RectanglesCanvas.ClearValue(WidthProperty);
         RectanglesCanvas.ClearValue(HeightProperty);
+        TemplateRegionOverlayCanvas.ClearValue(WidthProperty);
+        TemplateRegionOverlayCanvas.ClearValue(HeightProperty);
         GrabFrameImage.ClearValue(WidthProperty);
         GrabFrameImage.ClearValue(HeightProperty);
         IsOcrValid = false;