Hide install-time setup plumbing from the command listing

The setup group is described as interactive setup wizards, but these three
are not that. omarchy-setup-system is the ISO's entry point in the target
chroot, omarchy-setup-hardware is what it calls for device quirks, and
omarchy-setup-lock is called by install/config/lockscreen-pam.sh. None of
them is something to browse to and run.

Hiding only affects listings, so the ISO and the install leaves keep routing
through the CLI exactly as before.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

bin/omarchy-setup-system

@@ -4,6 +4,7 @@
 # omarchy:group=setup
 # omarchy:requires-sudo=true
 # omarchy:examples=omarchy setup system --install-user dhh --first-install
+# omarchy:hidden=true
 
 set -euo pipefail