fix: 替换 Java 11 API stripTrailing 为 Java 8 兼容写法

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

ruoyi-mill/src/main/java/com/ruoyi/mill/protocol/TelegramCodec.java

@@ -69,7 +69,7 @@ public class TelegramCodec {
                 case STRING: {
                     byte[] bytes = new byte[fd.getLength()];
                     buf.get(bytes);
-                    String s = new String(bytes, StandardCharsets.US_ASCII).stripTrailing();
+                    String s = new String(bytes, StandardCharsets.US_ASCII).replaceAll("\\s+$", "");
                     result.put(fd.getName(), s);
                     break;
                 }