feat(dashboard): add date filter and stat groups components

- Implemented DashboardDateFilter component for selecting date ranges including custom options.
- Created DashboardStatGroups component to display various statistical cards grouped by categories.
- Added dashboard-chart-data module to handle chart specifications and data processing for dashboard charts.
- Introduced Chart component with tooltip and legend functionalities for better data visualization.

Backend/ERPCore/Dtos/Dashboard/DashboardChartsDtos.cs

@@ -0,0 +1,46 @@
+namespace ERPCore.Dtos.Dashboard;
+
+/// <summary>
+/// Every dataset behind the dashboard graphs, in one computed-on-read object (same idea as
+/// <see cref="DashboardStatsDto"/>). Time-based sets follow the From-To period the dashboard filter sends;
+/// "snapshot" sets (ageing, batches expiring, low stock, warranties) describe what is open now.
+/// Purchases-vs-sales by month and stock value by warehouse are already in <see cref="DashboardStatsDto"/>.
+/// </summary>
+public sealed record DashboardChartsDto(
+    // Sales
+    IReadOnlyList<DailySalesPointDto> DailySales,
+    IReadOnlyList<ChartPointDto> PaymentSplit,
+    IReadOnlyList<ChartPointDto> TopItems,
+    IReadOnlyList<ChartPointDto> SalesByCategory,
+    IReadOnlyList<ChartPointDto> SalesByCustomer,
+    IReadOnlyList<DocumentStatusDto> DocumentStatus,
+    // Money
+    IReadOnlyList<ChartPointDto> CashInHandByDay,
+    IReadOnlyList<ChartPointDto> ReceivablesAgeing,
+    IReadOnlyList<ChartPointDto> PayablesAgeing,
+    IReadOnlyList<ChartPointDto> ExpenseBreakdown,
+    // Purchasing
+    IReadOnlyList<ChartPointDto> TopVendors,
+    // Stock
+    IReadOnlyList<ChartPairDto> StockInVsOut,
+    IReadOnlyList<ChartPointDto> BatchesExpiring,
+    // HR
+    IReadOnlyList<ChartPointDto> AttendanceMix,
+    IReadOnlyList<ChartPointDto> PayrollCostByMonth,
+    IReadOnlyList<ChartPointDto> LeaveStatus,
+    // Service and production
+    IReadOnlyList<ChartPairDto> TicketsOverTime,
+    IReadOnlyList<ChartPointDto> ProductionStatus,
+    IReadOnlyList<ChartPointDto> WarrantyExpiryByMonth);
+
+/// <summary>One labelled value: a bar, a donut slice or a point on a line.</summary>
+public sealed record ChartPointDto(string Label, decimal Value);
+
+/// <summary>Two values under one label (stock in/out by warehouse, tickets opened/resolved by day).</summary>
+public sealed record ChartPairDto(string Label, decimal First, decimal Second);
+
+/// <summary>One day of the Daily Sales, Gross Profit and Expenses line chart.</summary>
+public sealed record DailySalesPointDto(string Label, decimal Sales, decimal GrossProfit, decimal Expenses);
+
+/// <summary>Draft / Posted / Cancelled counts for one kind of document.</summary>
+public sealed record DocumentStatusDto(string Doc, int Draft, int Posted, int Cancelled);