RC ISO installs from the rc package channel

pacman-online-rc.conf's [omarchy] repo moves from pkgs.omarchy.org/edge to
pkgs.omarchy.org/rc: an RC ISO now bundles and installs the release-candidate
packages against the package set stable users will get, instead of edge
churn.

configs/pacman-online-rc.conf

@@ -27,7 +27,7 @@ Include = /etc/pacman.d/mirrorlist
 
 [omarchy]
 SigLevel = Optional TrustAll
-Server = https://pkgs.omarchy.org/edge/$arch
+Server = https://pkgs.omarchy.org/rc/$arch
 
 [arch-mact2]
 Server = https://mirror.funami.tech/arch-mact2/os/x86_64