feat: enhance dashboard report with receivables and discounts calculations

Distribution/Features/DashboardReport/DashboardReportDTOs.cs

@@ -2,21 +2,27 @@ namespace Distribution.Features.DashboardReport;
 
 public record DashboardFilter(DateTime From, DateTime To, Guid? RegionId, Guid? CategoryId, Guid? WarehouseId);
 
-public record SalesTotals(decimal GrossSales, decimal ReturnValue, int Orders, decimal CostedSales, decimal CostOfSales);
+public record SalesTotals(decimal GrossSales, decimal ReturnValue, decimal Discounts, int Orders, decimal CostedSales, decimal CostOfSales);
 
 public record SalesKpis(
-    decimal GrossSales, decimal ReturnValue, decimal NetSales, int Orders, decimal AverageOrderValue,
+    decimal GrossSales, decimal ReturnValue, decimal Discounts, decimal NetSales, int Orders, decimal AverageOrderValue,
     decimal GrossProfit, decimal? GrossProfitMarginPercent);
 
 public record SalesKpiComparison(SalesKpis Current, SalesKpis Previous, DateTime PreviousFrom, DateTime PreviousTo);
 
+public record ReceivablesTotals(decimal Collected, decimal Outstanding, decimal Overdue);
+
+public record CashKpis(decimal Collected, decimal Outstanding, decimal Overdue, decimal? CollectionRatePercent);
+
+public record CashKpiComparison(CashKpis Current, CashKpis Previous);
+
 public record TrendPoint(string Period, decimal Sales, decimal Returns);
 
 public record NamedAmount(Guid? Id, string Name, decimal Amount);
 
 public record SalesSummaryResponse(
     DateTime From, DateTime To, string Granularity,
-    SalesKpiComparison Kpis, List<TrendPoint> Trend,
+    SalesKpiComparison Kpis, CashKpiComparison Cash, List<TrendPoint> Trend,
     List<NamedAmount> ByCategory, List<NamedAmount> ByRegion, List<NamedAmount> ByRep);
 
 public record PeriodAmount(DateTime Date, decimal Amount);