Merge quattro and route refreshes through omarchy-update-pacman

Upstream now runs every Omarchy-owned pacman transaction through the
hidden omarchy-update-pacman helper so a mid-transaction systemd reexec
cannot kill it. Keep the deferred pre-refresh-pacman hook and the
command-scoped sudo wrapper, and call the helper from the refresh and
channel commands; the wrapper still applies to the helper's own sudo.

The sudo boundary fixture copies the helper into its root and runs a
systemd-run stand-in that execs the wrapped pacman step in place.

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>

bin/omarchy-channel-set

@@ -47,7 +47,7 @@ validate_dev_checkout() {
 
 link_dev_checkout() {
   local checkout="$1" required
-  [[ -d $checkout/.git ]] || git clone https://github.com/basecamp/omarchy.git "$checkout"
+  [[ -d $checkout/.git ]] || git clone https://github.com/omacom/omarchy.git "$checkout"
 
   # Check the destination before changing /etc/omarchy.conf or sudo's path.
   # An existing checkout is not pulled automatically and may predate this policy.
@@ -94,6 +94,10 @@ case "$channel" in
     ;;
 esac
 
+# A failure past this point leaves the channel switch half-applied, so say how
+# to pick it back up rather than dying silently under set -e.
+trap 'echo -e "\nThe channel switch did not complete. Review the error above, then rerun: omarchy-channel-set '"$channel"'" >&2' ERR
+
 if [[ -z $dev_checkout && $OMARCHY_PATH != "/usr/share/omarchy" ]]; then
   leaving_dev=1
 fi
@@ -107,7 +111,7 @@ fi
 
 omarchy-refresh-pacman "$pacman_channel" defer-hook
 # --ask 4 accepts omarchy <-> omarchy-dev replacement prompts without file overwrites.
-sudo env OMARCHY_UPDATE_PACMAN=1 pacman -S --needed --noconfirm --ask 4 "${packages[@]}"
+omarchy-update-pacman -S --needed --noconfirm --ask 4 "${packages[@]}"
 
 if [[ -z $dev_checkout ]]; then
   omarchy-dev-unlink --no-reboot