Correct the China docs and move .cn twins in the rc repository migration

test/shell.d/region-switch-test.sh

@@ -66,3 +66,13 @@ if output=$(omarchy-region mars 2>&1); then
   fail "an unknown region is refused" "$output"
 fi
 pass "an unknown region is refused"
+
+rc_migration="$test_tmp/1788112314.sh"
+rewrite "$ROOT/migrations/1788112314.sh" "$rc_migration"
+cp "$ROOT/default/pacman/mirrorlist-rc" "$root/etc/pacman.d/mirrorlist"
+sed -e 's|pkgs.omarchy.org/rc/|pkgs.omarchy.org/edge/|' "$ROOT/default/pacman/pacman-rc.conf" |
+  sed -f "$ROOT/default/region/china/pacman.sed" >"$root/etc/pacman.conf"
+bash -e "$rc_migration" >/dev/null
+[[ $(grep '^Server' "$root/etc/pacman.conf") == $'Server = https://pkgs.omarchy.cn/rc/$arch\nServer = https://pkgs.omarchy.org/rc/$arch' ]] ||
+  fail "the rc repository migration moves the .cn twin with its .org server" "$(grep '^Server' "$root/etc/pacman.conf")"
+pass "the rc repository migration moves the .cn twin with its .org server"