phase-10: add backoffice sandbox with mock business domain management

src/app/facades/backoffice/backoffice.facade.ts

@@ -0,0 +1,40 @@
+import { Injectable, signal } from '@angular/core';
+import { HttpClient } from '@angular/common/http';
+import { ProductCardConfig, CategoryCardConfig } from '../../shared/models/ui';
+
+@Injectable({ providedIn: 'root' })
+export class BackofficeFacade {
+  readonly products = signal<ProductCardConfig[]>([]);
+  readonly categories = signal<CategoryCardConfig[]>([]);
+  readonly loading = signal(false);
+
+  constructor(private readonly http: HttpClient) {}
+
+  load(): void {
+    this.loading.set(true);
+
+    this.http.get<ProductCardConfig[]>('/assets/mock/bootstrap/products.json').subscribe({
+      next: (products) => {
+        this.products.set(products ?? []);
+        this.loadCategories();
+      },
+      error: () => {
+        this.products.set([]);
+        this.loadCategories();
+      }
+    });
+  }
+
+  private loadCategories(): void {
+    this.http.get<CategoryCardConfig[]>('/assets/mock/bootstrap/categories.json').subscribe({
+      next: (categories) => {
+        this.categories.set(categories ?? []);
+        this.loading.set(false);
+      },
+      error: () => {
+        this.categories.set([]);
+        this.loading.set(false);
+      }
+    });
+  }
+}