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/emojis/Emojis.qml

@@ -247,7 +247,7 @@ Item {
             anchors.left: parent.left
             anchors.right: parent.right
             anchors.verticalCenter: parent.verticalCenter
-            text: root.filterText || "Search emojis…"
+            text: root.filterText || I18n.tr("Search emojis…")
             color: root.foreground
             opacity: root.filterText ? 1 : 0.58
             font.family: root.fontFamily
@@ -325,7 +325,7 @@ Item {
 
             Text {
               textFormat: Text.PlainText
-              text: "No matches for “" + root.filterText + "”"
+              text: I18n.tr("No matches for “%1”", root.filterText)
               color: root.foreground
               opacity: 0.7
               font.family: root.fontFamily