feat: 实现订单超时自动取消功能，支持钱包余额解冻和 Asynq Scheduler 统一调度

- 新增 expires_at 字段和复合索引，待支付订单 30 分钟超时自动取消
- 实现 cancelOrder/unfreezeWalletForCancel 钱包余额解冻逻辑
- 创建 Asynq 定时任务（order_expire/alert_check/data_cleanup）
- 将原有 time.Ticker 轮询迁移至 Asynq Scheduler 统一调度
- 同步 delta specs 到 main specs 并归档变更

internal/store/postgres/order_store.go

@@ -133,6 +133,16 @@ func (s *OrderStore) List(ctx context.Context, opts *store.QueryOptions, filters
 	if v, ok := filters["end_time"]; ok {
 		query = query.Where("created_at <= ?", v)
 	}
+	if v, ok := filters["is_expired"]; ok {
+		isExpired, _ := v.(bool)
+		if isExpired {
+			// 已过期：expires_at 不为空且小于当前时间，且订单仍为待支付状态
+			query = query.Where("expires_at IS NOT NULL AND expires_at <= NOW() AND payment_status = ?", model.PaymentStatusPending)
+		} else {
+			// 未过期：expires_at 为空或 expires_at 大于当前时间
+			query = query.Where("expires_at IS NULL OR expires_at > NOW()")
+		}
+	}
 
 	if err := query.Count(&total).Error; err != nil {
 		return nil, 0, err
@@ -156,13 +166,17 @@ func (s *OrderStore) List(ctx context.Context, opts *store.QueryOptions, filters
 	return orders, total, nil
 }
 
-func (s *OrderStore) UpdatePaymentStatus(ctx context.Context, id uint, status int, paidAt *time.Time) error {
+func (s *OrderStore) UpdatePaymentStatus(ctx context.Context, id uint, status int, paidAt *time.Time, expiresAt ...*time.Time) error {
 	updates := map[string]any{
 		"payment_status": status,
 	}
 	if paidAt != nil {
 		updates["paid_at"] = paidAt
 	}
+	// 支持可选的 expiresAt 参数，用于支付成功后清除过期时间或取消时清除过期时间
+	if len(expiresAt) > 0 {
+		updates["expires_at"] = expiresAt[0]
+	}
 	return s.db.WithContext(ctx).Model(&model.Order{}).Where("id = ?", id).Updates(updates).Error
 }
 
@@ -171,3 +185,19 @@ func (s *OrderStore) GenerateOrderNo() string {
 	randomNum := rand.Intn(1000000)
 	return fmt.Sprintf("ORD%s%06d", now.Format("20060102150405"), randomNum)
 }
+
+// FindExpiredOrders 查询已超时的待支付订单
+// 查询条件：expires_at <= NOW() AND payment_status = 1（待支付）
+// limit 参数限制每次批量处理的数量，避免一次性加载太多数据
+func (s *OrderStore) FindExpiredOrders(ctx context.Context, limit int) ([]*model.Order, error) {
+	var orders []*model.Order
+	err := s.db.WithContext(ctx).
+		Where("expires_at IS NOT NULL AND expires_at <= NOW() AND payment_status = ?", model.PaymentStatusPending).
+		Order("expires_at ASC").
+		Limit(limit).
+		Find(&orders).Error
+	if err != nil {
+		return nil, err
+	}
+	return orders, nil
+}