fix(backoffice): add error+retry states to Users, Monitoring, Analytics, Reports

Phase 8 (RC-01): these 4 list/dashboard pages had no error-state handling
on their primary data-load subscriptions — on a gateway error, `loading`
was either never reset (Users, Monitoring, Analytics: genuine infinite-
spinner risk, nested subscribe chain in Analytics never resolved on
failure) or there was no loading/empty/error handling at all (Reports
queue: raw table with zero skeleton or fallback).

- admin-users.facade.ts, admin-monitoring.facade.ts: add `error` signal,
  error callback on the primary load subscribe so `loading` always
  resolves.
- admin-analytics.facade.ts: add `error` signal; every level of the
  4-deep nested gateway subscribe chain (orders -> products ->
  categories -> reviews) now has an error handler that resolves loading
  instead of leaving it stuck true.
- admin-moderation.facade.ts: add `reportsLoading`/`reportsError` signals
  (reports list had none previously).
- Templates: reuse existing `app-skeleton`/`app-empty-state`/`app-button`
  primitives for the new error branch, `common.retry` label, two new
  generic `common.errorTitle`/`common.errorDescription` i18n keys added
  to en/ru/hy (reused across all 4 fixes instead of one-off per-page
  copy).

Verified: tsc --noEmit clean, `npm run build` green (pre-existing bundle-
budget warning only, unrelated). Live-checked Home (375px) and Backoffice
Products (1024px) — no console errors, tables/cards render without
overflow.

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

src/app/features/admin/analytics/facade/admin-analytics.facade.ts

@@ -38,6 +38,7 @@ export class AdminAnalyticsFacade {
 
   readonly dateRange = signal<AdminAnalyticsDateRange>(30);
   readonly loading = signal(false);
+  readonly error = signal(false);
   readonly summary = signal<AdminAnalyticsSummary | null>(null);
   readonly salesSeries = signal<AdminAnalyticsSeriesPoint[]>([]);
   readonly topProducts = signal<AdminAnalyticsTopProduct[]>([]);
@@ -63,6 +64,7 @@ export class AdminAnalyticsFacade {
 
   load(): void {
     this.loading.set(true);
+    this.error.set(false);
     this.dashboardFacade.ensureLoaded();
     this.recentActivity.set(
       this.dashboardFacade.activityEntries().map(entry => ({
@@ -72,44 +74,58 @@ export class AdminAnalyticsFacade {
       })),
     );
 
-    this.ordersGateway.loadOrders({ search: '', status: 'all', page: 1, pageSize: 100000 }).pipe(take(1)).subscribe(orderResult => {
-      const cutoff = Date.now() - this.dateRange() * 24 * 60 * 60 * 1000;
-      const inRange = orderResult.items.filter(order => new Date(order.createdAt).getTime() >= cutoff);
+    const fail = (): void => { this.loading.set(false); this.error.set(true); };
 
-      this.salesSeries.set(this.buildSeries(inRange, this.dateRange()));
-      this.topProducts.set(this.buildTopProducts(inRange));
-      this.customerAnalytics.set(this.buildCustomerAnalytics(orderResult.items, inRange, this.dateRange()));
+    this.ordersGateway.loadOrders({ search: '', status: 'all', page: 1, pageSize: 100000 }).pipe(take(1)).subscribe({
+      next: orderResult => {
+        const cutoff = Date.now() - this.dateRange() * 24 * 60 * 60 * 1000;
+        const inRange = orderResult.items.filter(order => new Date(order.createdAt).getTime() >= cutoff);
 
-      const revenueTotal = inRange.reduce((sum, order) => sum + order.total, 0);
-      const ordersCount = inRange.length;
-      const uniqueCustomers = new Set(inRange.map(order => order.customer.email)).size;
+        this.salesSeries.set(this.buildSeries(inRange, this.dateRange()));
+        this.topProducts.set(this.buildTopProducts(inRange));
+        this.customerAnalytics.set(this.buildCustomerAnalytics(orderResult.items, inRange, this.dateRange()));
 
-      this.productsGateway.loadProducts({ search: '', categoryId: null, visibility: 'all', stock: 'all', includeArchived: true, sort: 'title', page: 1, pageSize: 100000 }).pipe(take(1)).subscribe(productResult => {
-        this.categoriesGateway.loadCategories({ search: '', visibility: 'all', includeDeleted: true }).pipe(take(1)).subscribe(categories => {
-          this.moderationGateway.loadReviews({ search: '', status: 'all', rating: 'all', page: 1, pageSize: 100000 }).pipe(take(1)).subscribe(reviewResult => {
-            const products = productResult.items;
-            const reviews = reviewResult.items;
+        const revenueTotal = inRange.reduce((sum, order) => sum + order.total, 0);
+        const ordersCount = inRange.length;
+        const uniqueCustomers = new Set(inRange.map(order => order.customer.email)).size;
 
-            this.summary.set({
-              revenueTotal,
-              currency: inRange[0]?.currency ?? 'RUB',
-              ordersCount,
-              avgOrderValue: ordersCount > 0 ? Math.round(revenueTotal / ordersCount) : 0,
-              productsCount: products.length,
-              categoriesCount: categories.length,
-              customersCount: uniqueCustomers,
-              conversionRate: null,
+        this.productsGateway.loadProducts({ search: '', categoryId: null, visibility: 'all', stock: 'all', includeArchived: true, sort: 'title', page: 1, pageSize: 100000 }).pipe(take(1)).subscribe({
+          next: productResult => {
+            this.categoriesGateway.loadCategories({ search: '', visibility: 'all', includeDeleted: true }).pipe(take(1)).subscribe({
+              next: categories => {
+                this.moderationGateway.loadReviews({ search: '', status: 'all', rating: 'all', page: 1, pageSize: 100000 }).pipe(take(1)).subscribe({
+                  next: reviewResult => {
+                    const products = productResult.items;
+                    const reviews = reviewResult.items;
+
+                    this.summary.set({
+                      revenueTotal,
+                      currency: inRange[0]?.currency ?? 'RUB',
+                      ordersCount,
+                      avgOrderValue: ordersCount > 0 ? Math.round(revenueTotal / ordersCount) : 0,
+                      productsCount: products.length,
+                      categoriesCount: categories.length,
+                      customersCount: uniqueCustomers,
+                      conversionRate: null,
+                    });
+
+                    this.lowStockProducts.set(this.buildLowStock(products));
+                    this.productAnalytics.set(this.buildProductAnalytics(products));
+                    this.marketplaceHealth.set(this.buildMarketplaceHealth(products, categories, reviews, orderResult.items));
+                    this.recommendations.set(this.buildRecommendations(products, categories));
+
+                    this.loading.set(false);
+                  },
+                  error: fail
+                });
+              },
+              error: fail
             });
-
-            this.lowStockProducts.set(this.buildLowStock(products));
-            this.productAnalytics.set(this.buildProductAnalytics(products));
-            this.marketplaceHealth.set(this.buildMarketplaceHealth(products, categories, reviews, orderResult.items));
-            this.recommendations.set(this.buildRecommendations(products, categories));
-
-            this.loading.set(false);
-          });
+          },
+          error: fail
         });
-      });
+      },
+      error: fail
     });
   }
 

src/app/features/admin/analytics/pages/admin-analytics-page.component.html

@@ -11,6 +11,14 @@
     </div>
   </div>
 
+  @if (facade.error()) {
+    <app-empty-state [title]="'common.errorTitle' | translate" [description]="'common.errorDescription' | translate">
+      <span slot="actions">
+        <app-button variant="primary" (click)="facade.load()">{{ 'common.retry' | translate }}</app-button>
+      </span>
+    </app-empty-state>
+  } @else {
+
   <div class="tabs" role="tablist" [attr.aria-label]="'adminAnalytics.tabsLabel' | translate">
     @for (tab of tabs; track tab) {
       <button
@@ -245,4 +253,5 @@
       </div>
     </div>
   }
+  }
 </section>