feat: 实现订单支付功能模块

- 新增订单管理、支付回调、购买验证等核心服务
- 实现订单、订单项目的数据存储层和 API 接口
- 添加订单数据库迁移和 DTO 定义
- 更新 API 文档和路由配置
- 同步 3 个新规范到主规范库（订单管理、订单支付、套餐购买验证）
- 完成 OpenSpec 变更归档

Ultraworked with Sisyphus

internal/bootstrap/stores.go

@@ -35,6 +35,8 @@ type stores struct {
 	ShopPackageAllocation             *postgres.ShopPackageAllocationStore
 	ShopPackageAllocationPriceHistory *postgres.ShopPackageAllocationPriceHistoryStore
 	ShopSeriesCommissionStats         *postgres.ShopSeriesCommissionStatsStore
+	Order                             *postgres.OrderStore
+	OrderItem                         *postgres.OrderItemStore
 }
 
 func initStores(deps *Dependencies) *stores {
@@ -69,5 +71,7 @@ func initStores(deps *Dependencies) *stores {
 		ShopPackageAllocation:             postgres.NewShopPackageAllocationStore(deps.DB),
 		ShopPackageAllocationPriceHistory: postgres.NewShopPackageAllocationPriceHistoryStore(deps.DB),
 		ShopSeriesCommissionStats:         postgres.NewShopSeriesCommissionStatsStore(deps.DB),
+		Order:                             postgres.NewOrderStore(deps.DB, deps.Redis),
+		OrderItem:                         postgres.NewOrderItemStore(deps.DB, deps.Redis),
 	}
 }