feat: 集成Flyway数据库版本管理，迁移SQL文件到db/migration目录

src/main/resources/application.yml

@@ -14,12 +14,12 @@ spring:
     hikari:
       initialization-fail-timeout: 60000
 
-  # 自动执行建表SQL
-  sql:
-    init:
-      mode: always
-      schema-locations: classpath:sql/init.sql
-      data-locations: classpath:sql/data.sql
+  # Flyway 数据库版本管理
+  flyway:
+    enabled: true
+    baseline-on-migrate: true
+    locations: classpath:db/migration
+    baseline-version: 0
 
   # Redis配置 - 环境变量注入
   redis:

src/main/resources/db/migration/V2__add_discount_money.sql

@@ -0,0 +1,2 @@
+-- 订单表增加 discount_money 字段
+ALTER TABLE orders ADD COLUMN discount_money DECIMAL(12,2) DEFAULT 0;