feat(admin): order management

Sprint 23.

New features/admin/orders/ module, same container/facade/service split as
admin/products and admin/categories.

- AdminOrder model + AdminOrdersLocalGateway seeding 24 deterministic
  synthetic orders (no real order data source exists anywhere in this
  repo - explicitly a placeholder, not a mock of production volume)
- list: search, status filter, pagination, CSV export (client-side Blob
  download)
- detail: customer/payment/shipping, itemized total, status timeline,
  change-status dropdown, refund request + cancel (window.confirm-gated),
  separate customer-facing vs internal notes, print invoice via
  window.print() with @media print hiding non-invoice chrome
- wired into /:lang/backoffice/orders(/:id), replacing the coming-soon
  placeholder

docs/ADMIN.md + docs/BACKEND.md updated; dashboard's Orders/Revenue cards
(Sprint 19) remain intentionally un-wired to this mock and still render
pending-backend.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

src/app/app.routes.ts

@@ -98,8 +98,11 @@ const coreRoutes: Routes = [
       },
       {
         path: 'orders',
-        loadComponent: () => import('./features/backoffice/shared/backoffice-coming-soon-page.component').then(m => m.BackofficeComingSoonPageComponent),
-        data: { titleKey: 'dashboard.actionOrders' }
+        loadComponent: () => import('./features/admin/orders/pages/admin-orders-list-page.component').then(m => m.AdminOrdersListPageComponent)
+      },
+      {
+        path: 'orders/:id',
+        loadComponent: () => import('./features/admin/orders/pages/admin-order-detail-page.component').then(m => m.AdminOrderDetailPageComponent)
       },
       {
         path: 'media',