fix: 延期订单超时不关闭、无法继续支付、不能作废

- 支付宝查单把 ACQ.TRADE_NOT_EXIST 当成查单失败，恢复任务永远判为未知，订单停在待支付；
  同一套餐再下单时旧单也关不掉，新单无法创建。改为按"渠道无此订单"处理，过支付截止后关闭
- 延期订单详情对未过期的待支付订单返回 qr_content，后台可展示二维码、H5 可继续支付
- 新增作废待支付订单：后台 POST /orders/:id/close、H5 POST /orders/:id/cancel；作废前先查单，已支付则按支付成功办理

internal/handler/app/client_package_silence.go

@@ -145,6 +145,31 @@ func (h *ClientPackageSilenceHandler) GetOrder(c *fiber.Ctx) error {
 	return response.Success(c, result)
 }
 
+// CancelOrder 客户作废自己未支付的延期订单。POST /api/c/v1/package-silence/orders/:id/cancel
+func (h *ClientPackageSilenceHandler) CancelOrder(c *fiber.Ctx) error {
+	id, err := c.ParamsInt("id")
+	if err != nil || id <= 0 {
+		return errors.New(errors.CodeInvalidParam)
+	}
+	var req dto.SilenceOrderCancelRequest
+	if len(c.Body()) > 0 {
+		if err := c.BodyParser(&req); err != nil {
+			return errors.New(errors.CodeInvalidParam)
+		}
+	}
+	ctx, customerID, err := h.customerContext(c)
+	if err != nil {
+		return err
+	}
+	result, err := h.extensions.CancelPendingOrder(ctx, packagesilenceapp.CancelOrderCommand{
+		OrderID: uint(id), Scope: packagesilenceapp.Scope{CustomerID: customerID}, Reason: req.Reason,
+	})
+	if err != nil {
+		return err
+	}
+	return response.Success(c, result)
+}
+
 // ListRecords 套餐沉默期流水。GET /api/c/v1/package-silence/records
 func (h *ClientPackageSilenceHandler) ListRecords(c *fiber.Ctx) error {
 	var req dto.SilenceRecordListRequest