fix: data.sql插入前先删除数据

src/main/resources/sql/data.sql

@@ -1,4 +1,15 @@
 -- 测试数据
+-- 先删除已有数据
+DELETE FROM stock_flow;
+DELETE FROM order_items;
+DELETE FROM orders;
+DELETE FROM stock;
+DELETE FROM products;
+DELETE FROM categories;
+DELETE FROM customers;
+DELETE FROM users;
+DELETE FROM system_config;
+
 -- 用户表 - 管理员和销售
 INSERT INTO users (user_id, username, phone, password, role, status) VALUES 
 ('u-admin-001', 'admin', '13800000001', '$2a$10$N.zmdr9k7uOCQb376NoUnuTJ8iAt6Z5EHsM8lE9lBOsl7iAt6Z5EH', 'admin', 1),