fix: schema.sql 迁移语句移到索引创建之前，避免 product_id 列不存在时索引创建失败

demo/db/schema.sql

@@ -113,11 +113,6 @@ CREATE TABLE IF NOT EXISTS deal (
     created_at      TIMESTAMPTZ NOT NULL DEFAULT now()
 );
 
-CREATE INDEX IF NOT EXISTS idx_deal_salesperson ON deal(salesperson_id);
-CREATE INDEX IF NOT EXISTS idx_deal_customer ON deal(customer_id);
-CREATE INDEX IF NOT EXISTS idx_deal_date ON deal(deal_date);
-CREATE INDEX IF NOT EXISTS idx_deal_product ON deal(product_id);
-
 -- 迁移：为已存在的 deal 表补充 product_id 列（首次执行时若列已存在则跳过）
 DO $$
 BEGIN
@@ -132,6 +127,11 @@ BEGIN
     END IF;
 END $$;
 
+CREATE INDEX IF NOT EXISTS idx_deal_salesperson ON deal(salesperson_id);
+CREATE INDEX IF NOT EXISTS idx_deal_customer ON deal(customer_id);
+CREATE INDEX IF NOT EXISTS idx_deal_date ON deal(deal_date);
+CREATE INDEX IF NOT EXISTS idx_deal_product ON deal(product_id);
+
 -- 预置产品数据（幂等）
 INSERT INTO product (id, name, category, spec, price, description, positioning, selling_points, target_audience) VALUES
     (1, '益童宝益生菌', '儿童益生菌', '3盒套餐', 798.00,