fix: increase max zoom and handle GDI+ thread race in PlateView

Raise ViewScaleMax from 3000 to 10000 for deeper zoom. Catch
InvalidOperationException in hoverTimer_Elapsed when GraphicsPath is
concurrently used by the paint thread.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

OpenNest/Controls/DrawControl.cs

@@ -29,7 +29,7 @@ namespace OpenNest.Controls
         {
             ViewScale = 1.0f;
             ViewScaleMin = 0.3f;
-            ViewScaleMax = 3000;
+            ViewScaleMax = 10000;
             origin = new PointF(100, 100);
         }
 

OpenNest/Controls/PlateView.cs

@@ -627,6 +627,8 @@ namespace OpenNest.Controls
         {
             var graphPt = PointControlToGraph(hoverPoint);
             LayoutPart hitPart = null;
+            try
+            {
                 for (var i = parts.Count - 1; i >= 0; --i)
                 {
                     if (parts[i].Path.GetBounds().Contains(graphPt) &&
@@ -636,6 +638,12 @@ namespace OpenNest.Controls
                         break;
                     }
                 }
+            }
+            catch (InvalidOperationException)
+            {
+                // GraphicsPath in use by paint thread — skip this hover tick
+                return;
+            }
 
             hoveredPart = hitPart;
             showTooltip = hitPart != null;