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/dispute/arbitration.go

@@ -124,8 +124,10 @@ func (r *Repository) Arbitrate(ctx context.Context, adminID uint64, id uint64, r
 					return err
 				}
 			}
-			if err := rentergrowth.AwardOrderCompleted(tx, &order, actualSettlement.PureCoinAmountCent, rentergrowth.SourceOrderCompleted); err != nil {
-				return err
+			if order.DistributionSiteID == nil || *order.DistributionSiteID == 0 {
+				if err := rentergrowth.AwardOrderCompleted(tx, &order, actualSettlement.PureCoinAmountCent, rentergrowth.SourceOrderCompleted); err != nil {
+					return err
+				}
 			}
 		}
 		if err := tx.Save(&order).Error; err != nil {

backend/internal/modules/dispute/arbitration_deposit_hold_distribution_test.go

@@ -141,4 +141,10 @@ func TestArbitrationDistributionRefundUsesActualRefundWithDepositHold(t *testing
 		t.Fatalf("分销快照 net_paid_amount_cent = %d, want %d（毛收入 %d − 实际租金退款 %d）",
 			snapshot.NetPaidAmountCent, wantNetPaid, order.RentAmountCent, wantRentRefundCent)
 	}
+
+	var growthLogsCount int64
+	db.Model(&model.RenterGrowthLedger{}).Where("order_id = ?", order.ID).Count(&growthLogsCount)
+	if growthLogsCount != 0 {
+		t.Fatalf("分销订单仲裁不应发放用户成长积分，但产生了 %d 条记录", growthLogsCount)
+	}
 }