fix(cluster): update Asterisk CLI health check command to core show uptime

scripts/nexus-cluster

@@ -65,7 +65,7 @@ case "$CMD" in
         ;;
 
     check)
-        if pidof asterisk >/dev/null 2>&1 && /usr/sbin/asterisk -rx "core ping" 2>/dev/null | grep -q "Pong"; then
+        if pidof asterisk >/dev/null 2>&1 && /usr/sbin/asterisk -rx "core show uptime" 2>/dev/null | grep -qi "uptime"; then
             echo "HEALTHY"
         else
             echo "DEGRADED"