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/widgets/SystemUpdate.qml

@@ -58,7 +58,7 @@ BarWidget {
     bar: root.bar
     text: "\uf021"
     slotSize: Style.bar.statusSlot
-    tooltipText: "Pending Omarchy Updates"
+    tooltipText: I18n.tr("Pending Omarchy Updates")
     onPressed: root.runUpdate()
   }
 }