问题根因：数据库中 Flyway V7 记录的是 add registration refactoring tables，与代码中的

V7__add_judge_invite_referee_type.sql 不一致，导致 referee_type 字段从未被添加到
martial_judge_invite 表。

   已修复：
   1. 创建了新的迁移脚本 V9__add_judge_invite_referee_type.sql
   2. 手动在数据库中添加了 referee_type 字段
   3. 更新了 Flyway 历史记录

src/main/resources/db/migration/V9__add_judge_invite_referee_type.sql

@@ -0,0 +1,20 @@
+-- =====================================================
+-- Migration: Add referee_type to martial_judge_invite
+-- Version: V9
+-- Description: Add referee type column (1-Chief Judge, 2-Judge, 3-General Judge)
+-- Date: 2026-01-24
+-- =====================================================
+
+-- Idempotent: Only add column if not exists
+SET @dbname = DATABASE();
+SET @tablename = 'martial_judge_invite';
+SET @columnname = 'referee_type';
+SET @preparedStatement = (SELECT IF(
+  (SELECT COUNT(*) FROM INFORMATION_SCHEMA.COLUMNS 
+   WHERE TABLE_SCHEMA = @dbname AND TABLE_NAME = @tablename AND COLUMN_NAME = @columnname) > 0,
+  'SELECT 1',
+  CONCAT('ALTER TABLE ', @tablename, ' ADD COLUMN ', @columnname, ' INT DEFAULT NULL COMMENT "裁判类型：1-主裁判，2-裁判员，3-总裁"')
+));
+PREPARE alterIfNotExists FROM @preparedStatement;
+EXECUTE alterIfNotExists;
+DEALLOCATE PREPARE alterIfNotExists;