fix: map archive index metadata columns

internal/service/gameking/archive_safety.go

@@ -33,7 +33,13 @@ func ensureActivityEnableSafetyTx(tx *gorm.DB) error {
 func requireBackfillIndexOnDB(db *gorm.DB) error {
 	var columns []backfillIndexColumn
 	if err := db.Raw(`
-SELECT COLUMN_NAME, SEQ_IN_INDEX, SUB_PART, INDEX_TYPE, IS_VISIBLE
+-- 与任务中心 GC 门禁保持相同映射规则；不加别名时 MySQL 的大写列标签不会填充
+-- 显式小写 GORM tag，导致真实存在的 Game King 索引也被误判为缺失。
+SELECT COLUMN_NAME AS column_name,
+       SEQ_IN_INDEX AS seq_in_index,
+       SUB_PART AS sub_part,
+       INDEX_TYPE AS index_type,
+       IS_VISIBLE AS is_visible
 FROM information_schema.STATISTICS
 WHERE TABLE_SCHEMA = DATABASE()
   AND TABLE_NAME = 'task_center_event_archive_outbox'

internal/service/taskcenter/archive_gc_control.go

@@ -198,7 +198,13 @@ func (s *Service) requireArchiveGCClaimIndex(ctx context.Context) error {
 	}
 	var columns []indexColumn
 	if err := s.db.WithContext(ctx).Raw(`
-SELECT COLUMN_NAME, SEQ_IN_INDEX, SUB_PART, INDEX_TYPE, IS_VISIBLE
+-- MySQL 会把 information_schema 列标签原样返回为大写；显式使用与 GORM tag
+-- 一致的小写别名，避免查询有三行但结构体字段全为零值而误判索引缺失。
+SELECT COLUMN_NAME AS column_name,
+       SEQ_IN_INDEX AS seq_in_index,
+       SUB_PART AS sub_part,
+       INDEX_TYPE AS index_type,
+       IS_VISIBLE AS is_visible
 FROM information_schema.STATISTICS
 WHERE TABLE_SCHEMA = DATABASE()
   AND TABLE_NAME = 'task_center_event_archive_outbox'