feat(admin): build shared admin shell

Sidebar (Dashboard/Catalog group/Products/Categories/Orders/Transactions/
Reviews/Reports/Content/Media/Marketplace Builder/Users/Settings/
Monitoring/Analytics + Documentation/Help/Logout), sticky topbar
(breadcrumbs, page title/description, search, notifications, tenant
selector and quick-publish placeholders, current user), reserved
right-rail slot, scrollable content area. Desktop 280px sidebar, tablet
icon rail, mobile drawer with focus management and Escape-to-close.

Nav items without a built page (Reviews, Reports, Settings, Docs, Help)
render disabled with a coming-soon badge instead of dead links; Content
and Marketplace Builder route to the existing project-editor pages
(static-pages / general) rather than duplicating them.

All 15 /backoffice/** routes now render through AdminLayoutComponent;
the public storefront header/back-button/footer no longer render on
admin routes (app.ts/app.html gate on a new isAdminRoute signal).

Added the adminShell i18n namespace (ru/en/hy) for every new shell
string so this doesn't add to the existing untranslated-admin-UI gap
tracked in KNOWN-ISSUES.md.

Colors/type sizes follow DESIGN.md tokens; the two rgba() modal-scrim
values are a documented, intentional exception (neutral overlay,
not a themed token).

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

src/app/i18n/translations.ts

@@ -967,4 +967,61 @@ export interface Translations {
     topProductsEmptyTitle: string;
     topProductsEmptyDescription: string;
   };
+  adminShell: {
+    skipToContent: string;
+    openSidebar: string;
+    closeSidebar: string;
+    collapseSidebar: string;
+    expandSidebar: string;
+    nav: {
+      dashboard: string;
+      catalogGroup: string;
+      products: string;
+      categories: string;
+      orders: string;
+      transactions: string;
+      reviews: string;
+      reports: string;
+      content: string;
+      mediaLibrary: string;
+      marketplaceBuilder: string;
+      users: string;
+      settings: string;
+      monitoring: string;
+      analytics: string;
+      documentation: string;
+      help: string;
+      logout: string;
+      comingSoonBadge: string;
+    };
+    topbar: {
+      searchLabel: string;
+      searchPlaceholder: string;
+      notifications: string;
+      notificationsEmpty: string;
+      account: string;
+      tenantSelector: string;
+      tenantSelectorComingSoon: string;
+      quickPublish: string;
+      quickPublishComingSoon: string;
+    };
+    breadcrumbHome: string;
+    pages: {
+      dashboard: { title: string; description: string };
+      products: { title: string; description: string };
+      productCreate: { title: string; description: string };
+      productEdit: { title: string; description: string };
+      productDuplicate: { title: string; description: string };
+      categories: { title: string; description: string };
+      categoryCreate: { title: string; description: string };
+      categoryEdit: { title: string; description: string };
+      orders: { title: string; description: string };
+      orderDetail: { title: string; description: string };
+      transactions: { title: string; description: string };
+      media: { title: string; description: string };
+      users: { title: string; description: string };
+      monitoring: { title: string; description: string };
+      analytics: { title: string; description: string };
+    };
+  };
 }