feat(quickshell): add minimal bar rendering on both monitors

- Variants + PanelWindow, one per Quickshell.screens entry
- ShellScreen-typed modelData, pragma ComponentBehavior: Bound
  required to reference id across delegate boundary
- screen: modelData is required for placement; modelData alone
  only supplies per-instance data, not physical binding

quickshell/.config/quickshell/shell.qml

@@ -0,0 +1,28 @@
+pragma ComponentBehavior: Bound
+
+import QtQuick
+import Quickshell
+
+ShellRoot {
+    Variants {
+        model: Quickshell.screens
+        PanelWindow {
+            id : panel
+            required property ShellScreen modelData
+            property string monitorName: modelData.name
+            screen: modelData
+            anchors {
+                right : true
+                top : true
+                left : true
+            }
+            implicitHeight: 32
+            color : "#2b1618"
+            Text {
+                anchors.centerIn: parent
+                text : "Hello from " + panel.monitorName
+                color : '#f2e4d8'
+            }
+        }
+    }
+}