fix: validateHierarchy 增加 parentType null 守卫，防止 switch NPE

Spec review 发现：MenuType.fromCode() 对未知 DB 值返回 null 时，switch 表达式会抛 NPE 500，
改为提前抛 BusinessErrorException 并附带 menuType 值，便于排查脏数据。

crm-auth/src/main/java/com/crm/auth/service/impl/ResourceServiceImpl.java

@@ -178,6 +178,10 @@ public class ResourceServiceImpl implements IResourceService {
             throw new BusinessErrorException(CODE_RESOURCE_INVALID, "父节点不存在：parentId=" + node.getParentId());
         }
         MenuType parentType = MenuType.fromCode(parent.getMenuType());
+        if (parentType == null) {
+            throw new BusinessErrorException(CODE_RESOURCE_INVALID,
+                    "父节点类型未知：menuType=" + parent.getMenuType());
+        }
 
         if (!MenuType.isLegalChild(parentType, childType)) {
             String msg = switch (parentType) {