fix(vortex-dns): Fix shell glob syntax error in zone list

Remove 2>/dev/null from for-loop glob pattern which causes syntax
error in BusyBox ash shell. The [ -f "$zf" ] check handles the
case when no zone files exist.

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

package/secubox/secubox-vortex-dns/files/usr/sbin/vortexctl

@@ -444,7 +444,7 @@ cmd_zone_list() {
 	done
 
 	# Also list zone files not in UCI
-	for zf in "$ZONE_DIR"/*.zone 2>/dev/null; do
+	for zf in "$ZONE_DIR"/*.zone; do
 		[ -f "$zf" ] || continue
 		local domain=$(basename "$zf" .zone)
 		if ! uci show "$CONFIG" 2>/dev/null | grep -q "domain='$domain'"; then