feat: add ghost button

AppGhostButton.qml

@@ -0,0 +1,21 @@
+import QtQuick
+import QtQuick.Controls.Basic
+import QtQuick.Controls.impl // Needed for features like the Control.blend() function
+import DesignSystem
+
+Button {
+    id: control
+    font.family: Fonts.dotrice
+    font.bold: false
+
+    background: Rectangle {
+        // NOTE: copied from ~/Qt/6.8.3/macos/qml/QtQuick/Controls/Basic/Button.qml
+        implicitWidth: 100
+        implicitHeight: 40
+        visible: !control.flat || control.down || control.checked || control.highlighted
+        color: control.down ? "transparent" : Theme.card
+        border.width: 0
+        // custom
+        radius: Theme.radius
+    }
+}

CMakeLists.txt

@@ -14,6 +14,7 @@ set(plain_qml_files
   AppIcon.qml
   AppPrimaryButton.qml
   AppSecondaryButton.qml
+  AppGhostButton.qml
   AppCard.qml
   AppCaption.qml
   AppHeadline.qml

gallery/Main.qml

@@ -33,6 +33,9 @@ AppWindow {
         AppSecondaryButton {
           text: "Secondary button"
         }
+        AppGhostButton {
+          text: "Ghost"
+        }
       }
 
       AppCard {