fix(distribution): 修复收号站订单详情权限、专属支付通道路由、大盘统计与仲裁积分隔离

- 修复 FindOrder 在收号站模式(two_party_distributor_receive / three_party)下的 403 权限判定，放行参与方站点成员并精准计算收益
- 串联 distribution_site_payment_channels 至 payment.Start 核心支付发起流程，分销订单优先使用绑定的专属商户通道
- 修复数据大盘 GetDashboardAnalytics 趋势中 ReceivedCount 恒为 0 的问题，并对齐今日订单与 GMV 统计
- 修复 dispute/arbitration.go 仲裁完成时向分销租客发放成长积分的泄漏风险
- 提现管理新增 distribution_site_name/distribution_site_code 字段并在后台列表与详情弹窗中区分展示分销站
- GetPublicSiteInfo 增加 X-Distribution-Site-Code 请求头兜底支持

backend/internal/modules/distribution/auth_onboard_test.go

@@ -2,12 +2,15 @@ package distribution
 
 import (
 	"context"
+	"net/http"
+	"net/http/httptest"
 	"testing"
 
+	"github.com/gin-gonic/gin"
+	"golang.org/x/crypto/bcrypt"
+
 	"hfb_sys/backend/internal/model"
 	"hfb_sys/backend/internal/modules/auth"
-
-	"golang.org/x/crypto/bcrypt"
 )
 
 func TestOnboardSiteAndLoginFlow(t *testing.T) {
@@ -176,3 +179,32 @@ func TestOnboardSiteAndLoginFlow(t *testing.T) {
 		t.Fatalf("unexpected profile: %#v", profile)
 	}
 }
+
+func TestGetPublicSiteInfoHeaderFallback(t *testing.T) {
+	db := distributionTestDB(t)
+	repo := NewRepository(db)
+	svc := NewService(repo, nil)
+	handler := NewHandler(svc)
+
+	site := model.DistributionSite{
+		SiteCode: "header_site",
+		SiteName: "头部测试站",
+		Domain:   "header.example.com",
+		Status:   "active",
+	}
+	if err := db.Create(&site).Error; err != nil {
+		t.Fatal(err)
+	}
+
+	gin.SetMode(gin.TestMode)
+	w := httptest.NewRecorder()
+	c, _ := gin.CreateTestContext(w)
+	req, _ := http.NewRequest("GET", "/api/v1/distribution/public/site-info", nil)
+	req.Header.Set("X-Distribution-Site-Code", "header_site")
+	c.Request = req
+
+	handler.GetPublicSiteInfo(c)
+	if w.Code != http.StatusOK {
+		t.Fatalf("expected 200, got %d, body: %s", w.Code, w.Body.String())
+	}
+}