Calendar is no longer a Widget, moved to Modules/Calendar/Calendar.qml

- Using a NLoader
- Got a display bug with DayOfWeekRow!

shell.qml

@@ -8,6 +8,7 @@ import Quickshell.Services.Pipewire
 import qs.Widgets
 import qs.Modules.Audio
 import qs.Modules.Bar
+import qs.Modules.Calendar
 import qs.Modules.DemoPanel
 import qs.Modules.Background
 import qs.Modules.SidePanel
@@ -37,4 +38,8 @@ ShellRoot {
   AudioDeviceSelector {
     id: audioDeviceSelector
   }
+
+  Calendar {
+    id: calendar
+  }
 }