fix(v0.11): 第六轮走查——legacy 去除 System.out 演示入口与 Kafka 消费端日志

- AESUtils / RSAUtils / SM4Utils / CustomXssUtil / SnowFlakeSerialCode：删除仅用于本地演示的 main，消除生产源码中的 System.out。
- KafkaConsumer：移除 printStackTrace；异常改为 logger.error(msg, e)；Class.newInstance 改为 getDeclaredConstructor().newInstance()。

对应 docs/reviews 05 工程卫生项；全量 maven-cloudwalk-legacy-public 已通过 compile。

Made-with: Cursor

maven-cloudwalk-legacy-public/cloudwalk-common-serial/src/main/java/cn/cloudwalk/serial/worker/SnowFlakeSerialCode.java

@@ -279,29 +279,6 @@ this.workId = workId;
 }
 }
 
-public static void main(String[] args) throws Exception {
-Enumeration<NetworkInterface> en = NetworkInterface.getNetworkInterfaces();
-StringBuilder sb = new StringBuilder();
-ArrayList<String> tmpMacList = new ArrayList<>();
-while (en.hasMoreElements()) {
-NetworkInterface iface = en.nextElement();
-List<InterfaceAddress> addrs = iface.getInterfaceAddresses();
-for (InterfaceAddress addr : addrs) {
-InetAddress ip = addr.getAddress();
-NetworkInterface network = NetworkInterface.getByInetAddress(ip);
-if (network == null)
-continue;  byte[] mac = network.getHardwareAddress();
-if (mac == null)
-continue;  sb.delete(0, sb.length());
-for (int i = 0; i < mac.length; ) { sb.append(String.format("%02X%s", new Object[] { Byte.valueOf(mac[i]), (i < mac.length - 1) ? "-" : "" })); i++; }
-tmpMacList.add(sb.toString());
-} 
-}  if (tmpMacList.size() <= 0) {
-System.out.println("mac地址列表为空");
-}
-for (String mac : tmpMacList)
-System.out.println(mac); 
-}
 }