Drop western default apps from the CN default set

Basecamp, Discord, HEY, Google Contacts/Maps/Messages/Photos,
WhatsApp, and X lose their shipped launchers, webapp keybindings,
and the whatsapp-slim extension; aether, libreoffice-fresh, and
obs-studio leave the base package set. The HEY mailto handler and
its registration go with them. Preinstall add/remove lists, the
launcher hide list, and chromium flags stay in sync.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01QKxGW1raAWaqeU8WdHsMsp

config/chromium-flags.conf

@@ -2,4 +2,4 @@
 --ozone-platform-hint=wayland
 --password-store=gnome-libsecret
 --enable-features=TouchpadOverscrollHistoryNavigation
---load-extension=/usr/share/omarchy/default/chromium/extensions/copy-url,/usr/share/omarchy/default/chromium/extensions/yt-dlp,/usr/share/omarchy/default/chromium/extensions/whatsapp-slim
+--load-extension=/usr/share/omarchy/default/chromium/extensions/copy-url,/usr/share/omarchy/default/chromium/extensions/yt-dlp