feat(admin): implement order and customer operations experience

Orders dashboard (real orders-today/pending/paid/cancelled/refunded/customers/returning-customers/average-order/recent-activity/system-alerts, computed from the full order book not just the current page); orders list gains density, saved column visibility, bulk status change/archive/delete/export/print alongside existing search+status filter+pagination, sticky table header; order detail gets a visual status workflow stepper in business language (Pending/Packing/Shipping/Completed, with Cancelled/Refunded as terminal states) and a reusable OrderTimelineComponent replacing the flat text log; added a derived Customers feature (list + profile detail: statistics/lifetime value/addresses/orders/activity/notes) built entirely by grouping existing AdminOrder records by email - no new backend, no invented gateway, since no customer entity existed. Added archive/restore/delete to the orders gateway (soft-delete pattern mirroring categories) and filled in the adminOrders/adminCustomers i18n namespaces, which previously didn't exist at all (every adminOrders.* label was rendering as a raw key).

src/app/app.routes.ts

@@ -167,6 +167,24 @@ const coreRoutes: Routes = [
           breadcrumb: [{ labelKey: 'adminShell.nav.orders', path: ['orders'] }, { labelKey: 'adminShell.pages.orderDetail.title' }]
         }
       },
+      {
+        path: 'customers',
+        loadComponent: () => import('./features/admin/customers/pages/admin-customers-list-page.component').then(m => m.AdminCustomersListPageComponent),
+        data: {
+          titleKey: 'adminShell.pages.customers.title',
+          descriptionKey: 'adminShell.pages.customers.description',
+          breadcrumb: [{ labelKey: 'adminShell.nav.customers' }]
+        }
+      },
+      {
+        path: 'customers/:email',
+        loadComponent: () => import('./features/admin/customers/pages/admin-customer-detail-page.component').then(m => m.AdminCustomerDetailPageComponent),
+        data: {
+          titleKey: 'adminShell.pages.customerDetail.title',
+          descriptionKey: 'adminShell.pages.customerDetail.description',
+          breadcrumb: [{ labelKey: 'adminShell.nav.customers', path: ['customers'] }, { labelKey: 'adminShell.pages.customerDetail.title' }]
+        }
+      },
       {
         path: 'media',
         loadComponent: () => import('./features/backoffice/media/media-library-page.component').then(m => m.MediaLibraryPageComponent),