新增查询绑定结果接口（自建发货页轮询角色信息）

- GET /api/client/v1/orders/{order_no}/delivery/bind-result?bind_uuid=xxx
- 返回 bound/game_account/role_name/game_channel；未绑定返回 bound=false（不报错，供轮询）
- 对接文档自建发货页模式新增该接口，注明轮询建议间隔

backend/internal/service/delivery.go

@@ -128,9 +128,14 @@ type DeliveryProduct struct {
 }
 
 type DeliveryBindResult struct {
-	BindUUID string `json:"bind_uuid"`
-	BindURL  string `json:"bind_url"`
-	QRURL    string `json:"qr_url"`
+	BindUUID    string `json:"bind_uuid"`
+	BindURL     string `json:"bind_url"`
+	QRURL       string `json:"qr_url"`
+	Bound       bool   `json:"bound"`
+	GameAccount string `json:"game_account,omitempty"`
+	RoleName    string `json:"role_name,omitempty"`
+	GameChannel string `json:"game_channel,omitempty"`
+	Message     string `json:"message,omitempty"`
 }
 
 type DeliveryLinkResult struct {
@@ -194,6 +199,37 @@ func (s *DeliveryService) BindForMerchant(merchantID uint, orderNo, gameAccount
 	return s.bindWithOrder(orderNo, gameAccount, nil, merchantID)
 }
 
+// GetBindResult 查询绑定结果（自建发货页轮询用）。
+// 绑定未完成时返回 bound=false（不报错），由前端提示继续扫码。
+func (s *DeliveryService) GetBindResult(merchantID uint, orderNo, bindUUID string) (*DeliveryBindResult, error) {
+	bindUUID = strings.TrimSpace(bindUUID)
+	if bindUUID == "" {
+		return nil, errors.New("bind_uuid 不能为空")
+	}
+	openOrder, order, goodID, err := s.loadMerchantOrder(merchantID, orderNo)
+	if err != nil {
+		return nil, err
+	}
+	if _, _, _, err := s.buildDeliveryState(openOrder, order, goodID, false); err != nil {
+		return nil, err
+	}
+	account, err := s.accountBound(bindUUID, goodID)
+	if err != nil {
+		if strings.Contains(err.Error(), "尚未绑定") || strings.Contains(err.Error(), "未绑定") {
+			return &DeliveryBindResult{BindUUID: bindUUID, Bound: false, Message: "尚未绑定，请先完成扫码绑定"}, nil
+		}
+		return nil, err
+	}
+	return &DeliveryBindResult{
+		BindUUID:    bindUUID,
+		Bound:       true,
+		GameAccount: stringFromMap(account, "game_account"),
+		RoleName:    stringFromMap(account, "game_account_role_name"),
+		GameChannel: gameChannelText(account),
+		Message:     "绑定成功",
+	}, nil
+}
+
 func (s *DeliveryService) bindWithOrder(orderNo, gameAccount string, auth *DeliveryLinkAuth, merchantID uint) (*DeliveryBindResult, error) {
 	gameAccount = strings.TrimSpace(gameAccount)
 	if gameAccount == "" {