fix(ImComboBox): Fix inverted scrolling with natural scrolling enabled

Use Qt's built-in event.inverted flag to detect natural scrolling instead
of platform-specific detection. When natural scrolling is enabled, invert
the wheel delta so that scrolling down always moves to the next item in
the combo box, matching user expectations for discrete item selection.

This approach is simpler, cross-platform, and relies on Qt's native
scroll direction handling rather than querying system preferences.

Author: tdewey-rpi

src/qmlcomponents/ImComboBox.qml

@@ -26,8 +26,6 @@ ComboBox {
 
     // Enhanced properties
     property bool indicateError: false
-    // Wheel scrolling configuration (no inertia for closed state)
-    property bool wheelInvert: false
 
     // Internal search functionality
     property string searchString: ""
@@ -176,11 +174,20 @@ ComboBox {
         onWheel: (event) => {
             if (!root.popup.visible) {
                 var dy = event.pixelDelta && Math.abs(event.pixelDelta.y) > 0 ? event.pixelDelta.y : event.angleDelta.y
-                // Apply wheelInvert option if needed
-                if (root.wheelInvert) dy = -dy
-                // Negative delta = scroll down = move down list = increase index
-                // Positive delta = scroll up = move up list = decrease index
-                // (Qt already handles natural scrolling, so we use the raw delta)
+                
+                // Qt provides deltas that match the system scroll direction (natural vs traditional).
+                // However, for combo boxes (discrete item selection), users expect consistent behavior:
+                // "scroll down gesture" should always mean "next item" regardless of scroll preferences.
+                // 
+                // When event.inverted is true (natural scrolling), Qt's deltas are content-oriented,
+                // which feels backwards for discrete selection. We invert to match user expectations.
+                if (event.inverted) {
+                    dy = -dy
+                }
+                
+                // After adjustment:
+                // Negative delta = scroll down = next item (increase index)
+                // Positive delta = scroll up = previous item (decrease index)
                 if (dy < 0 && root.currentIndex < root.model.length - 1) {
                     root.currentIndex++
                 } else if (dy > 0 && root.currentIndex > 0) {