feat(db): add production migration chain

deploy/sql/migrations/overseas/baiyue_lastlag_warehouse/V2__retire_location_zone_and_rebuild_query_index.sql

@@ -0,0 +1,18 @@
+-- Region: OVERSEAS
+-- Schema: baiyue_lastlag_warehouse
+-- Purpose: 移除已退役的库位 zone_code，并重建不含 zone_code 的查询索引。
+-- Preconditions: 连接必须指向 baiyue_lastlag_warehouse；生产执行前必须单独授权 DROP COLUMN，并确认 zone_code 无外部读写依赖。
+-- Postconditions: wh_location 不再有 zone_code，idx_location_query 为 (customer_id, warehouse_id, status, deleted)。
+-- Safety: DROP COLUMN zone_code 是有意的破坏性结构变更；本文件只声明迁移，不执行生产授权或数据清理。
+
+SET NAMES utf8mb4;
+
+SET @ddl = IF(EXISTS (SELECT 1 FROM information_schema.statistics WHERE table_schema = DATABASE() AND table_name = 'wh_location' AND index_name = 'idx_location_query'),
+  'ALTER TABLE wh_location DROP INDEX idx_location_query', 'SELECT 1');
+PREPARE stmt FROM @ddl; EXECUTE stmt; DEALLOCATE PREPARE stmt;
+SET @ddl = IF(EXISTS (SELECT 1 FROM information_schema.columns WHERE table_schema = DATABASE() AND table_name = 'wh_location' AND column_name = 'zone_code'),
+  'ALTER TABLE wh_location DROP COLUMN zone_code', 'SELECT 1');
+PREPARE stmt FROM @ddl; EXECUTE stmt; DEALLOCATE PREPARE stmt;
+SET @ddl = IF(NOT EXISTS (SELECT 1 FROM information_schema.statistics WHERE table_schema = DATABASE() AND table_name = 'wh_location' AND index_name = 'idx_location_query'),
+  'ALTER TABLE wh_location ADD KEY idx_location_query (customer_id, warehouse_id, status, deleted)', 'SELECT 1');
+PREPARE stmt FROM @ddl; EXECUTE stmt; DEALLOCATE PREPARE stmt;