fix(admin): isolate login on admin host

Allow runtime request headers through API preflight and keep the storefront shell hidden while admin QR authentication gates backoffice.

src/app/app.html

@@ -10,6 +10,8 @@
     <p>{{ 'app.serverError' | translate }}</p>
     <button class="retry-btn" (click)="retryConnection()">{{ 'app.retryConnection' | translate }}</button>
   </div>
+} @else if (isAdminHost && !isAdminRoute()) {
+  <app-telegram-login mode="admin" />
 } @else if (isAdminRoute()) {
   <router-outlet></router-outlet>
   <app-telegram-login mode="admin" />
@@ -30,4 +32,4 @@
   }
   <!-- <app-telegram-login /> -->
   <app-telegram-login mode="admin" />
-}
+}

src/app/app.ts

@@ -28,6 +28,8 @@ import { TelegramLoginComponent } from './components/telegram-login/telegram-log
 })
 export class App implements OnInit {
   protected title = '';
+  readonly isAdminHost = typeof window !== 'undefined'
+    && window.location.hostname.toLowerCase().startsWith('admin.');
   isHomePage = signal(true);
   isAdminRoute = signal(false);
   checkingServer = signal(true);