feat: add dashboard overview stats endpoint and UI integration

- Implemented `GET /dashboard/stats` in `DashboardController` to provide aggregate counts for stock, GRN, and procurement.
- Created `DashboardStatsDto` and `WarehouseValuationDto` to structure the response data.
- Developed `DashboardService` to fetch and compute necessary statistics from the database.
- Added `IDashboardService` interface for service abstraction.
- Introduced API client methods in `dashboard.ts` for frontend consumption of the new endpoint.
- Defined TypeScript types for dashboard data in `dashboard.ts` to ensure type safety in the frontend.
- Updated UI components in the frontend to reflect changes in the dashboard, including styling adjustments and removal of unused icons.

Frontend/erp-system/lib/api/dashboard.ts

@@ -0,0 +1,9 @@
+// Dashboard overview endpoint (Backend/ERPCore/Controllers/DashboardController.cs).
+import { apiRequest } from "@/lib/api-client"
+import { DashboardStats } from "@/types/dashboard"
+
+export const dashboardApi = {
+  stats(): Promise<DashboardStats> {
+    return apiRequest<DashboardStats>("/dashboard/stats")
+  },
+}