feat(finance): add daily paid order count

backend/internal/modules/adminfinance/dashboard.go

@@ -222,6 +222,10 @@ func (r *Repository) dailyItems(ctx context.Context, query DashboardQuery) ([]Fi
 		Scan(&payments).Error; err != nil {
 		return nil, err
 	}
+	paidOrders, err := r.dailyPaidOrders(ctx, query)
+	if err != nil {
+		return nil, err
+	}
 
 	settlements := make([]dailySettlementRow, 0)
 	if err := db.Table("rental_orders AS ro").
@@ -307,6 +311,13 @@ func (r *Repository) dailyItems(ctx context.Context, query DashboardQuery) ([]Fi
 		item.PendingRefundCount = row.PendingRefundCount
 		itemsByDate[date] = item
 	}
+	for _, row := range paidOrders {
+		date := dailyDateKey(row.Date)
+		item := itemsByDate[date]
+		item.Date = date
+		item.PaidOrderCount = row.PaidOrderCount
+		itemsByDate[date] = item
+	}
 	for _, row := range settlements {
 		date := dailyDateKey(row.Date)
 		item := itemsByDate[date]
@@ -361,6 +372,19 @@ func (r *Repository) dailyItems(ctx context.Context, query DashboardQuery) ([]Fi
 	return items, nil
 }
 
+// dailyPaidOrders 仅统计普通租赁订单的成功支付，按实际支付完成时间归集。
+func (r *Repository) dailyPaidOrders(ctx context.Context, query DashboardQuery) ([]dailyPaidOrderRow, error) {
+	items := make([]dailyPaidOrderRow, 0)
+	err := r.db.WithContext(ctx).Table("payment_orders AS po").
+		Select(`DATE(po.paid_at) AS date,
+			COUNT(DISTINCT po.order_id) AS paid_order_count`).
+		Where("po.biz_type = ? AND po.status = ?", "order_pay", "paid").
+		Where("po.paid_at >= ? AND po.paid_at <= ?", query.StartDate, query.EndDate).
+		Group("DATE(po.paid_at)").
+		Scan(&items).Error
+	return items, err
+}
+
 type paymentSummaryRow struct {
 	TotalFlowAmountCent     int64
 	TotalRefundAmountCent   int64
@@ -398,6 +422,11 @@ type dailyPaymentRow struct {
 	PendingRefundCount      int64
 }
 
+type dailyPaidOrderRow struct {
+	Date           string
+	PaidOrderCount int64
+}
+
 type dailySettlementRow struct {
 	Date                               string
 	PlatformIncomeAmountCent           int64