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/system-power-test.sh

@@ -74,6 +74,7 @@ esac
 SH
 done
 chmod +x "$mock_bin"/*
+ln -s "$ROOT/bin/omarchy-text" "$mock_bin/omarchy-text"
 
 run_power_command() {
   local action="$1"