feat(order): 支持代购订单和强充要求检查

- OrderService 新增代购订单支持
  - 强充要求检查（首次购买最低充值）
  - 代购订单支付限制（无需支付）
  - 强充金额验证
- 新增 OrderDTO 请求/响应结构
  - PurchaseCheckRequest/Response（购买预检）
  - CreatePurchaseOnBehalfRequest（代购订单创建）
- Order 模型新增支付方式
  - PaymentMethodOffline（线下支付，仅平台代购使用）
- OrderService 依赖注入扩展
  - 新增 SeriesAllocationStore、IotCardStore、DeviceStore
  - 支持强充要求检查逻辑
- 完整的集成测试覆盖（534 行）
  - 代购订单创建、强充验证、支付限制等场景

Co-authored-by: Sisyphus <clio-agent@sisyphuslabs.ai>

internal/model/dto/order_dto.go

@@ -72,3 +72,25 @@ type PayOrderParams struct {
 	ID uint `path:"id" description:"订单ID" required:"true"`
 	PayOrderRequest
 }
+
+type PurchaseCheckRequest struct {
+	OrderType  string `json:"order_type" validate:"required,oneof=single_card device" required:"true" description:"订单类型 (single_card:单卡购买, device:设备购买)"`
+	ResourceID uint   `json:"resource_id" validate:"required,min=1" required:"true" description:"资源ID (IoT卡ID或设备ID)"`
+	PackageIDs []uint `json:"package_ids" validate:"required,min=1,max=10,dive,min=1" required:"true" minItems:"1" maxItems:"10" description:"套餐ID列表"`
+}
+
+type PurchaseCheckResponse struct {
+	TotalPackageAmount  int64  `json:"total_package_amount" description:"套餐总价(分)"`
+	NeedForceRecharge   bool   `json:"need_force_recharge" description:"是否需要强充"`
+	ForceRechargeAmount int64  `json:"force_recharge_amount" description:"强充金额(分)"`
+	ActualPayment       int64  `json:"actual_payment" description:"实际支付金额(分)"`
+	WalletCredit        int64  `json:"wallet_credit" description:"钱包到账金额(分)"`
+	Message             string `json:"message" description:"提示信息"`
+}
+
+type CreatePurchaseOnBehalfRequest struct {
+	OrderType  string `json:"order_type" validate:"required,oneof=single_card device" required:"true" description:"订单类型 (single_card:单卡购买, device:设备购买)"`
+	IotCardID  *uint  `json:"iot_card_id" validate:"required_if=OrderType single_card" description:"IoT卡ID(单卡购买时必填)"`
+	DeviceID   *uint  `json:"device_id" validate:"required_if=OrderType device" description:"设备ID(设备购买时必填)"`
+	PackageIDs []uint `json:"package_ids" validate:"required,min=1,max=10,dive,min=1" required:"true" minItems:"1" maxItems:"10" description:"套餐ID列表"`
+}

internal/model/order.go

@@ -63,9 +63,10 @@ const (
 
 // 支付方式常量
 const (
-	PaymentMethodWallet = "wallet" // 钱包支付
-	PaymentMethodWechat = "wechat" // 微信支付
-	PaymentMethodAlipay = "alipay" // 支付宝支付
+	PaymentMethodWallet  = "wallet"  // 钱包支付
+	PaymentMethodWechat  = "wechat"  // 微信支付
+	PaymentMethodAlipay  = "alipay"  // 支付宝支付
+	PaymentMethodOffline = "offline" // 线下支付(仅平台代购使用)
 )
 
 // 支付状态常量