feat(dashboard): 增加极品专区与保险成交统计

- 仪表盘新增今日极品专区、保险8%、保险4%成交数量
- 展示近7日每日成交趋势和明细
- 按已支付订单口径统计，补充回归测试

backend/internal/modules/admindashboard/repository.go

@@ -14,8 +14,11 @@ import (
 
 const (
 	listingDailyTrendDays         = 7
+	tradingDailyTrendDays         = 7
 	listingChannelWebsite         = "站内发布"
 	listingChannelExternalUnknown = "未填写"
+	// 成交口径：排除待支付、取消、关闭，与推广归因的成交统计保持一致。
+	tradingOrderPaidCondition = "status NOT IN ('pending_payment', 'cancelled', 'closed')"
 )
 
 type Repository struct {
@@ -78,6 +81,10 @@ func (r *Repository) Summary(ctx context.Context) (*DashboardDTO, error) {
 	if err != nil {
 		return nil, err
 	}
+	tradingDaily, err := r.tradingDailyOverview(ctx, now, tradingDailyTrendDays)
+	if err != nil {
+		return nil, err
+	}
 	manualEntryToday, err := r.manualEntryToday(ctx, now)
 	if err != nil {
 		return nil, err
@@ -94,6 +101,7 @@ func (r *Repository) Summary(ctx context.Context) (*DashboardDTO, error) {
 		Metrics:          metrics,
 		Pending:          pending,
 		ListingDaily:     listingDaily,
+		TradingDaily:     tradingDaily,
 		ManualEntryToday: manualEntryToday,
 		RecentOrders:     recentOrders,
 		RecentDisputes:   recentDisputes,
@@ -353,6 +361,76 @@ func isTradeLeaveEvent(eventType, source string) bool {
 	}
 }
 
+// tradingDailyOverview 统计经营成交数据：极品专区成交、保险 8%/4% 成交。
+// 订单在下单时已快照 is_premium / compensation_plan / insurance_fee_bps，
+// 因此按订单统计不受商品后续修改影响。
+func (r *Repository) tradingDailyOverview(ctx context.Context, now time.Time, days int) (TradingDailyOverviewDTO, error) {
+	if days <= 0 {
+		days = tradingDailyTrendDays
+	}
+	loc := timeutil.ShanghaiLocation()
+	now = now.In(loc)
+	end := time.Date(now.Year(), now.Month(), now.Day(), 0, 0, 0, 0, loc).AddDate(0, 0, 1)
+	start := end.AddDate(0, 0, -days)
+
+	type row struct {
+		CreatedAt        time.Time
+		IsPremium        bool
+		CompensationPlan string
+		InsuranceFeeBps  int
+	}
+	rows := make([]row, 0)
+	// 读取区间内订单后在 Go 侧按上海时区归日，避免依赖 MySQL 会话时区。
+	if err := r.db.WithContext(ctx).Table("rental_orders").
+		Select("created_at, is_premium, compensation_plan, insurance_fee_bps").
+		Where(tradingOrderPaidCondition).
+		Where("created_at >= ? AND created_at < ?", start, end).
+		Scan(&rows).Error; err != nil {
+		return TradingDailyOverviewDTO{}, err
+	}
+
+	byDay := make(map[string]TradingDayStatsDTO, days)
+	for _, item := range rows {
+		key := item.CreatedAt.In(loc).Format("2006-01-02")
+		stats := byDay[key]
+		stats.Date = key
+		if item.IsPremium {
+			stats.PremiumOrderCount++
+		}
+		if item.CompensationPlan == "insurance" {
+			switch item.InsuranceFeeBps {
+			case 800:
+				stats.Insurance8OrderCount++
+			case 400:
+				stats.Insurance4OrderCount++
+			}
+		}
+		byDay[key] = stats
+	}
+
+	trend := make([]TradingDayStatsDTO, 0, days)
+	for i := days - 1; i >= 0; i-- {
+		day := time.Date(now.Year(), now.Month(), now.Day(), 0, 0, 0, 0, loc).AddDate(0, 0, -i)
+		key := day.Format("2006-01-02")
+		item := TradingDayStatsDTO{Date: key}
+		if v, ok := byDay[key]; ok {
+			item = v
+		}
+		trend = append(trend, item)
+	}
+
+	today := TradingDayStatsDTO{Date: now.Format("2006-01-02")}
+	if len(trend) > 0 {
+		today = trend[len(trend)-1]
+	}
+	return TradingDailyOverviewDTO{
+		Today:    today,
+		Trend:    trend,
+		Days:     days,
+		Timezone: "Asia/Shanghai",
+	}, nil
+}
+
 // manualEntryToday 统计今日（北京时间自然日）各客服的手动录单数量。
 // 录单表是后来新增的功能表，若迁移尚未执行（表不存在）则降级为空统计，
 // 避免连带整个仪表盘不可用。