feat(wordcloud): 下单 WCD 派单（buildWcdPackage + dispatch + 幂等 + 订单设计关联）

src/orders/orders.service.ts

@@ -43,6 +43,8 @@ export class OrdersService {
       user: { connect: { id: userId } },
       totalAmount,
       addressSnapshot: dto.addressSnapshot as Prisma.InputJsonValue,
+      // 关联设计清单（R4 下单后 WCD 派单读取 designData；R3 契约 CreateOrderDto 已含该字段）
+      designList: dto.designListId ? { connect: { id: dto.designListId } } : undefined,
       items: {
         create: dto.items.map((it) => ({
           productId: it.productId,