feat(admin): sprint 19 admin dashboard, routing, i18n

- Add admin dashboard feature (models/gateway/facade/components/page)
- Wire admin/products routes and backoffice coming-soon placeholders
- Add lastPublishedAt to ProjectEditorFacade/state
- Add dashboard i18n keys (en/ru/hy) and docs/ADMIN.md

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

src/app/features/admin/dashboard/components/admin-dashboard-card.component.ts

@@ -0,0 +1,20 @@
+import { ChangeDetectionStrategy, Component, Input } from '@angular/core';
+import { CommonModule } from '@angular/common';
+import { TranslatePipe } from '../../../../i18n/translate.pipe';
+import { AdminDashboardCardStatus } from '../models/admin-dashboard.model';
+
+@Component({
+  selector: 'app-admin-dashboard-card',
+  standalone: true,
+  imports: [CommonModule, TranslatePipe],
+  templateUrl: './admin-dashboard-card.component.html',
+  styleUrls: ['./admin-dashboard-card.component.scss'],
+  changeDetection: ChangeDetectionStrategy.OnPush,
+})
+export class AdminDashboardCardComponent {
+  @Input() title = '';
+  @Input() status: AdminDashboardCardStatus = 'ready';
+  @Input() value: string | null = null;
+  @Input() subtitle: string | null = null;
+  @Input() icon: string | null = null;
+}