fix(interop): resolve native resource leaks in GTK and WebKit interop

Fix critical memory leaks identified in architecture review: Add signal handler disconnection in WebKitNative (load-changed and script-dialog signals now properly cleaned up), implement GTK idle callback cleanup with automatic removal on completion, add dlclose() calls for WebKit library handles, track GTK signal IDs in GtkSkiaSurfaceWidget for proper disposal. Replace empty catch blocks in GestureManager with logged exception handling. Add WebKitNative.Cleanup() and GtkNative.ClearCallbacks() methods for application shutdown.

Views/SkiaShell.cs

@@ -646,7 +646,7 @@ public class SkiaShell : SkiaLayoutView
                     var value = Convert.ChangeType(param.Value, prop.PropertyType);
                     prop.SetValue(content, value);
                 }
-                catch { }
+                catch (Exception ex) { DiagnosticLog.Debug("SkiaShell", "Parameter type conversion failed", ex); }
             }
         }
     }