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

@@ -627,15 +627,23 @@ namespace OpenNest.Controls
         {
             var graphPt = PointControlToGraph(hoverPoint);
             LayoutPart hitPart = null;
-            for (var i = parts.Count - 1; i >= 0; --i)
+            try
             {
-                if (parts[i].Path.GetBounds().Contains(graphPt) &&
-                    parts[i].Path.IsVisible(graphPt))
+                for (var i = parts.Count - 1; i >= 0; --i)
                 {
-                    hitPart = parts[i];
-                    break;
+                    if (parts[i].Path.GetBounds().Contains(graphPt) &&
+                        parts[i].Path.IsVisible(graphPt))
+                    {
+                        hitPart = parts[i];
+                        break;
+                    }
                 }
             }
+            catch (InvalidOperationException)
+            {
+                // GraphicsPath in use by paint thread — skip this hover tick
+                return;
+            }
 
             hoveredPart = hitPart;
             showTooltip = hitPart != null;