Dashboard metrics parallel fetching

sequenceDiagram autonumber participant UI as Dashboard participant Hook as useDashboardMetrics participant A as getItemCount participant B as getSupplierCount participant C as getLowStockCount participant HC as httpClient participant BE as Backend API UI->>Hook: render hook Hook->>Hook: Promise.all([A(), B(), C()]) par inventory count Hook->>A: call A->>HC: GET /api/inventory/count HC->>BE: request BE-->>HC: number HC-->>A: number A-->>Hook: number and supplier count Hook->>B: call B->>HC: GET /api/suppliers/count HC->>BE: request BE-->>HC: number HC-->>B: number B-->>Hook: number and low-stock count Hook->>C: call C->>HC: GET /api/analytics/low-stock/count HC->>BE: request BE-->>HC: number HC-->>C: number C-->>Hook: number end Hook-->>UI: { inventoryCount, suppliersCount, lowStockCount }