refactor finance.

API/ROLAC.API/Services/IFinanceDashboardService.cs

@@ -0,0 +1,18 @@
+using ROLAC.API.DTOs.Finance;
+namespace ROLAC.API.Services;
+
+public interface IFinanceDashboardService
+{
+    /// <summary>All-time balance: total Givings minus total Paid+Approved expenses.</summary>
+    Task<FinanceSummaryDto> GetSummaryAsync();
+
+    /// <summary>Income (Givings) vs expense (Paid+Approved) totals within the date range.</summary>
+    Task<IncomeExpenseDto> GetIncomeExpenseAsync(DateOnly? from, DateOnly? to);
+
+    /// <summary>
+    /// Expense totals grouped by the drill level implied by the supplied ids:
+    /// none -> by Ministry; ministryId -> by CategoryGroup; ministryId+categoryGroupId -> by SubCategory.
+    /// </summary>
+    Task<List<BreakdownSliceDto>> GetExpenseBreakdownAsync(
+        DateOnly? from, DateOnly? to, int? ministryId, int? categoryGroupId);
+}