Add Simplified Chinese as a system language

The installer asks for the language before the keyboard, and
Setup > Language (omarchy language en|zh) switches it later. Under
zh_CN the menu reads its labels from omarchy-menu.zh-cn.jsonc, the
shell from I18nZh.js through I18n.tr, and notifications are worded
by their sender through omarchy-text, which reads the same table.
User text is never translated.

shell/plugins/bar/indicators/Dnd.qml

@@ -11,8 +11,8 @@ BarIndicator {
   active: dnd
   activeText: "󰂛"
   inactiveText: "󰂛"
-  activeTooltipText: "Allow Notifications"
-  inactiveTooltipText: "Silence Notifications"
+  activeTooltipText: I18n.tr("Allow Notifications")
+  inactiveTooltipText: I18n.tr("Silence Notifications")
 
   onPressed: function() {
     if (root.notificationService) {