add wallpaper picker

modules/corners/ScreenCorners.qml

@@ -14,7 +14,7 @@ import qs.settings
 */
 Variants {
     model: Quickshell.screens
-    delegate: PanelWindow {
+    delegate: WlrLayershell {
         id: root
         required property ShellScreen modelData
         screen: modelData
@@ -24,9 +24,11 @@ Variants {
             left: true
             right: true
         }
-        margins.top: Config.floating ? 0 : Config.barHeight
+        margins {
+            top: Config.floating ? 0 : Config.barHeight
+        }
         mask: Region {
-            item: root
+            item: Item {}
         }
         color: 'transparent'
         exclusionMode: ExclusionMode.Ignore