fix(test): 修复测试文件类型错误和测试数据库 schema 过期问题

- 修正 stock_in/out 测试中 WarehouseID/ProductID 指针误用（StockOrder 用 uint64，Inventory 用 *uint64）
- 更新 testutil/setup.go：inventories 表加入所有批次字段，stock_in_items 加 production_date，新增 finance_records 表
- 修正 inventory handler 中 DATE_FORMAT（MySQL 专属）→ DATE()（跨 DB 兼容）
- 更新断言：order_no 前缀改为 RK，库存总量用 SUM 替代 First
- 库存 List 新增 in_stock=1 过滤器

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

backend/internal/handler/stock_out_test.go

@@ -25,8 +25,8 @@ func TestStockOutHandler_FullFlow(t *testing.T) {
 	// 先建立库存
 	db.Create(&model.Inventory{
 		ShopID:      shop.ID,
-		WarehouseID: warehouse.ID,
-		ProductID:   product.ID,
+		WarehouseID: &warehouse.ID,
+		ProductID:   &product.ID,
 		Quantity:    100,
 	})
 
@@ -83,8 +83,8 @@ func TestStockOutHandler_InsufficientStock(t *testing.T) {
 	// 库存只有 5
 	db.Create(&model.Inventory{
 		ShopID:      shop.ID,
-		WarehouseID: warehouse.ID,
-		ProductID:   product.ID,
+		WarehouseID: &warehouse.ID,
+		ProductID:   &product.ID,
 		Quantity:    5,
 	})
 
@@ -114,7 +114,7 @@ func TestStockOutHandler_List(t *testing.T) {
 	r := setupProtectedRouter(db)
 
 	// 先建立库存
-	db.Create(&model.Inventory{ShopID: shop.ID, WarehouseID: warehouse.ID, ProductID: product.ID, Quantity: 100})
+	db.Create(&model.Inventory{ShopID: shop.ID, WarehouseID: &warehouse.ID, ProductID: &product.ID, Quantity: 100})
 
 	// 创建 2 个出库单
 	for i := 0; i < 2; i++ {
@@ -142,7 +142,7 @@ func TestStockOutHandler_Reject(t *testing.T) {
 	token := getAuthToken(user.ID, shop.ID, "admin")
 	r := setupProtectedRouter(db)
 
-	db.Create(&model.Inventory{ShopID: shop.ID, WarehouseID: warehouse.ID, ProductID: product.ID, Quantity: 100})
+	db.Create(&model.Inventory{ShopID: shop.ID, WarehouseID: &warehouse.ID, ProductID: &product.ID, Quantity: 100})
 
 	w := makeRequest(r, "POST", "/api/v1/stock-out/orders", token, map[string]interface{}{
 		"warehouse_id": warehouse.ID,
@@ -206,8 +206,8 @@ func TestStockOutHandler_TenantIsolation(t *testing.T) {
 	// 建立门店 A 的库存
 	db.Create(&model.Inventory{
 		ShopID:      shopA.ID,
-		WarehouseID: warehouseA.ID,
-		ProductID:   productA.ID,
+		WarehouseID: &warehouseA.ID,
+		ProductID:   &productA.ID,
 		Quantity:    50,
 	})
 
@@ -259,7 +259,7 @@ func TestStockOutHandler_Approve_NotPending(t *testing.T) {
 	token := getAuthToken(user.ID, shop.ID, "admin")
 	r := setupProtectedRouter(db)
 
-	db.Create(&model.Inventory{ShopID: shop.ID, WarehouseID: warehouse.ID, ProductID: product.ID, Quantity: 50})
+	db.Create(&model.Inventory{ShopID: shop.ID, WarehouseID: &warehouse.ID, ProductID: &product.ID, Quantity: 50})
 
 	// 创建但不提交
 	w := makeRequest(r, "POST", "/api/v1/stock-out/orders", token, map[string]interface{}{
@@ -285,7 +285,7 @@ func TestStockOutHandler_InventoryLog_OnApprove(t *testing.T) {
 	token := getAuthToken(user.ID, shop.ID, "admin")
 	r := setupProtectedRouter(db)
 
-	db.Create(&model.Inventory{ShopID: shop.ID, WarehouseID: warehouse.ID, ProductID: product.ID, Quantity: 100})
+	db.Create(&model.Inventory{ShopID: shop.ID, WarehouseID: &warehouse.ID, ProductID: &product.ID, Quantity: 100})
 
 	// 创建、提交、审核
 	w := makeRequest(r, "POST", "/api/v1/stock-out/orders", token, map[string]interface{}{