Point the rc channel at the rc package repository

pacman-rc.conf shipped with [omarchy] on pkgs.omarchy.org/edge — a
leftover from when release candidates published there. Candidates now
publish to a dedicated rc channel, so a machine switched to rc with
omarchy-refresh-pacman was pairing the rc Arch mirror with edge omarchy
packages, and omarchy-version-channel could not name the rc repository
at all (an rc install reported 'rc / unknown').

Point the conf at pkgs.omarchy.org/rc, teach omarchy-version-channel
the rc repository, and repoint existing rc-channel machines with a
migration. The migration only rewrites the shipped pairing (rc mirror +
edge [omarchy]); an administrator's deliberate combination is kept.

bin/omarchy-version-channel

@@ -14,6 +14,8 @@ fi
 
 if grep -q "https://pkgs.omarchy.org/stable/" /etc/pacman.conf; then
   pkgs="stable"
+elif grep -q "https://pkgs.omarchy.org/rc/" /etc/pacman.conf; then
+  pkgs="rc"
 elif grep -q "https://pkgs.omarchy.org/edge/" /etc/pacman.conf; then
   pkgs="edge"
 else

default/pacman/pacman-rc.conf

@@ -26,4 +26,4 @@ Include = /etc/pacman.d/mirrorlist
 Include = /etc/pacman.d/mirrorlist
 
 [omarchy]
-Server = https://pkgs.omarchy.org/edge/$arch
+Server = https://pkgs.omarchy.org/rc/$arch

migrations/1788112314.sh

@@ -0,0 +1,12 @@
+echo "Point rc-channel installs at the rc package repository"
+
+# pacman-rc.conf shipped with [omarchy] pointing at the edge repository, a
+# leftover from when release candidates published there. Candidates now publish
+# to the dedicated rc channel, so a machine on the rc mirror was taking its
+# omarchy packages from edge. Repoint only a conf that still carries the
+# shipped pairing: an administrator who chose another combination keeps it.
+if grep -q "https://rc-mirror.omarchy.org/" /etc/pacman.d/mirrorlist &&
+  grep -q "^Server = https://pkgs.omarchy.org/edge/" /etc/pacman.conf; then
+  sudo sed -i "s|^Server = https://pkgs.omarchy.org/edge/|Server = https://pkgs.omarchy.org/rc/|" /etc/pacman.conf
+  echo "Switched the [omarchy] repository to the rc channel to match this machine's rc mirror."
+fi