Ask for the language first, and install in Chinese in a CJK console

The first screen offers English or Simplified Chinese. Chinese reruns
the configurator in cage + foot, which draw Chinese, with Noto Sans
Mono CJK unpacked from the offline mirror's noto-fonts-cjk; no font
joins the live image. There the keyboard list keeps US-keymap layouts
and preselects Chinese (Simplified, Pinyin), every later screen and
the install dashboard read in Chinese, and the target gets
LANG=zh_CN.UTF-8 through locale_config. Without a display or the
font, Chinese continues in English on the VT. The summary shows the
keyboard by its label instead of its keymap.

Needs omarchy's omarchy_prompt_language and omarchy_text in
install/provisioning/setup-form.sh.

builder/build-iso.sh

@@ -121,7 +121,8 @@ cp "/tmp/$NODE_FILENAME" "$build_cache_dir/airootfs/opt/packages/"
 # The selected omarchy-settings package is needed here so its post_install hook
 # drops Omarchy's plymouthd.conf into /etc/plymouth before mkarchiso builds the
 # live initramfs.
-arch_packages=(linux-t2 git gum jq openssl plymouth ttfx tzupdate omarchy-keyring "$OMARCHY_SETTINGS_PACKAGE" lvm2 cryptsetup parted)
+# cage and foot give Chinese installs a console that draws Chinese.
+arch_packages=(linux-t2 git gum jq openssl plymouth ttfx tzupdate omarchy-keyring "$OMARCHY_SETTINGS_PACKAGE" lvm2 cryptsetup parted cage foot)
 printf '%s\n' "${arch_packages[@]}" >> "$build_cache_dir/packages.x86_64"
 
 # The live ISO boots linux-t2 (see airootfs/etc/mkinitcpio.d/linux-t2.preset), so