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.

install/user/first-run/setup-agent.hook

@@ -5,7 +5,7 @@ set -e
 # Omarchy ships no default agent, so invite once rather than picking one. An
 # agent already chosen means the invitation has nothing to offer.
 if [[ -z $(omarchy-default-agent) ]] && omarchy-done ensure agent-setup-invitation; then
-  omarchy-notification-send -u critical -g 󰚩 "Set your default agent" \
-    "Let your favorite agent help with Omarchy." \
+  omarchy-notification-send -u critical -g 󰚩 "$(omarchy-text "Set your default agent")" \
+    "$(omarchy-text "Let your favorite agent help with Omarchy.")" \
     --exec omarchy menu summon setup.default.agent
 fi