feat(bar): Introduce core density scaling mechanism

Modules/Bar/Extras/BarWidgetLoader.qml

@@ -12,6 +12,19 @@ Item {
   property string section: widgetProps && widgetProps.section || ""
   property int sectionIndex: widgetProps && widgetProps.sectionWidgetIndex || 0
 
+  property string barDensity: "default"
+  readonly property real scaling: (function() {
+    switch (barDensity) {
+      case "mini":
+        return 0.8
+      case "compact":
+        return 0.9
+      case "comfortable":
+      default:
+        return 1.0
+    }
+  })()
+
   // Don't reserve space unless the loaded widget is really visible
   implicitWidth: getImplicitSize(loader.item, "implicitWidth")
   implicitHeight: getImplicitSize(loader.item, "implicitHeight")
@@ -40,6 +53,10 @@ Item {
             item[prop] = widgetProps[prop]
           }
         }
+        // Explicitly set scaling property
+        if (item.hasOwnProperty("scaling")) {
+            item.scaling = Qt.binding(function() { return root.scaling; })
+        }
       }
 
       // Register this widget instance with BarService