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.

test/shell.d/clock-test.sh

@@ -276,7 +276,7 @@ assert(/readonly property int lifeExpectancy: Model\.parseLifeExpectancy\(settin
 assert(/id: expectancyField/.test(panelSource) && /id: bornField/.test(panelSource), 'calendar offers both inputs')
 assert(/visible: root\.editingLife\s*\n\s*anchors\.horizontalCenter: parent\.horizontalCenter/.test(panelSource), 'calendar centers the inputs over the bar they replace')
 assert(/visible: root\.birthYear > 0/.test(panelSource), 'calendar hides the life bar until a birth year is known')
-assert(/text: "LIFE"/.test(panelSource) && /root\.lifeDone/.test(panelSource), 'calendar shows the life bar')
+assert(/text: I18n\.tr\("LIFE"\)/.test(panelSource) && /root\.lifeDone/.test(panelSource), 'calendar shows the life bar')
 assert(/text: "Memento Mori"/.test(panelSource), 'calendar names the life bar on hover')
 assert(/onDoubleTapped: root\.clearLife\(\)/.test(panelSource), 'calendar puts the life bar away when it is double-tapped')
 assert(/persistSettings\(\{ birthYear: 0 \}\)/.test(panelSource), 'calendar clears the birth year to hide the life bar')