feat: add inx ordering for tunnel and node

springboot-backend/src/main/java/com/admin/entity/Node.java

@@ -14,7 +14,7 @@ import lombok.EqualsAndHashCode;
  */
 @Data
 @EqualsAndHashCode(callSuper = true)
-public class Node extends BaseEntity {
+public class Node extends BaseEntity {
 
     private static final long serialVersionUID = 1L;
 
@@ -38,6 +38,12 @@ public class Node extends BaseEntity {
 
     private String tcpListenAddr;
 
-    private String udpListenAddr;
-
-}
+    private String udpListenAddr;
+
+    /**
+     * Display/order index for drag-sorting in admin UI.
+     * Lower value appears first.
+     */
+    private Integer inx;
+
+}