feat: add stats page for admin

frontend-admin/src/api/api_admin.ts

@@ -53,6 +53,30 @@ export const logoutAdmin = async (): Promise<void> => {
     }
 };
 
+// ── Types stats ──────────────────────────────────────────────────────────────
+export interface StatsSummary {
+    total_orders: number;
+    total_revenue: number;
+    peak_weekday: string;
+    top_product: string;
+    avg_per_day: number;
+}
+export interface WeekdayStat { weekday: string; count: number; }
+export interface DayStat     { day: string; label: string; count: number; }
+export interface ProductStat { product_id: number; name: string; quantity: number; order_count: number; revenue: number; }
+
+export interface AdminStats {
+    summary:      StatsSummary;
+    by_weekday:   WeekdayStat[];
+    by_day_30:    DayStat[];
+    top_products: ProductStat[];
+}
+
+export const getAdminStats = async (): Promise<AdminStats> => {
+    const { data } = await apiClient.get(`${V2}/admin/protected/stats`);
+    return data;
+};
+
 export const getAllClients = async (): Promise<ClientResponse[]> => {
     const { data } = await apiClient.get(`${V2}/admin/protected/all/clients`);
     return data.clients || [];