新增测试代码规范、修复响应体断言缺失与魔法数字

- AGENTS.md 新增测试代码专项规范：常量、fixture、触发器、HTTP断言、层边界说明
- TestUpdateAllocationExpiryBaseHTTP 补全 PATCH 响应体字段断言
- 四个集成测试文件以 testIDMask 局部常量替换 0x7fffffff 魔法数字

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

internal/service/order/package_terms_integration_test.go

@@ -1,5 +1,8 @@
 package order
 
+// testIDMask 用于将纳秒时间戳截断为合法的 uint 主键范围，仅限测试用。
+const testIDMask = testIDMask
+
 import (
 	"context"
 	"strconv"
@@ -20,7 +23,7 @@ func TestSynchronousPurchasePersistsImmutableTermsSnapshots(t *testing.T) {
 	card := createOrderTermsCard(t, tx, constants.RealNameStatusNotVerified)
 	formal := createOrderTermsPackage(t, tx, constants.PackageTypeFormal, constants.PackageExpiryBaseFromActivation, 45)
 	addon := createOrderTermsPackage(t, tx, constants.PackageTypeAddon, constants.PackageExpiryBaseFromActivation, 10)
-	shopID := uint(time.Now().UnixNano() & 0x7fffffff)
+	shopID := uint(time.Now().UnixNano() & testIDMask)
 	override := constants.PackageExpiryBaseFromPurchase
 	for _, packageID := range []uint{formal.ID, addon.ID} {
 		allocation := &model.ShopPackageAllocation{ShopID: shopID, PackageID: packageID, CostPrice: 1, RetailPrice: 2, Status: constants.StatusEnabled, ShelfStatus: 1, ExpiryBaseOverride: &override}
@@ -96,7 +99,7 @@ func TestCEndPurchasePersistsSnapshotAndActivatesImmediately(t *testing.T) {
 	service := &Service{shopPackageAllocationStore: postgres.NewShopPackageAllocationStore(tx), logger: zap.NewNop()}
 	now := time.Now()
 	order := &model.Order{
-		Model:     gorm.Model{ID: uint(time.Now().UnixNano() & 0x7fffffff)},
+		Model:     gorm.Model{ID: uint(time.Now().UnixNano() & testIDMask)},
 		OrderNo:   "UR55-CEND-" + strconv.FormatInt(time.Now().UnixNano(), 10),
 		OrderType: model.OrderTypeSingleCard,
 		BuyerType: model.BuyerTypePersonal,
@@ -168,6 +171,6 @@ func createOrderTermsPackage(t *testing.T, tx *gorm.DB, packageType, expiryBase
 }
 
 func newOrderTermsOrder(packageID, cardID uint, sellerShopID *uint) *model.Order {
-	orderID := uint(time.Now().UnixNano() & 0x7fffffff)
+	orderID := uint(time.Now().UnixNano() & testIDMask)
 	return &model.Order{Model: gorm.Model{ID: orderID}, OrderNo: "UR55-ORDER-" + strconv.FormatUint(uint64(orderID), 10), OrderType: model.OrderTypeSingleCard, BuyerType: model.BuyerTypeAgent, IotCardID: &cardID, SellerShopID: sellerShopID, TotalAmount: 100, Generation: 1}
 }