feat(admin-auth): add dev-only QR bypass via ?devBypassAdmin=true

Fabricates a local admin session and activates it directly, skipping the
Telegram QR flow, for local testing without a reachable session backend.
Guarded by environment.production at runtime - no-ops in production
builds even if this code ships.

src/app/app.ts

@@ -85,7 +85,13 @@ export class App implements OnInit {
     this.checkServerHealth();
   }
 
-  /** ?login=true / ?adminLogin=true open the respective login dialog for manual testing. No effect when absent. */
+  /**
+   * ?login=true / ?adminLogin=true open the respective login dialog for
+   * manual testing. ?devBypassAdmin=true skips the QR flow entirely and
+   * activates a fake local admin session - dev builds only, no effect (and
+   * no-ops server-side too, see AdminAuthService.devBypassLogin) in
+   * production. No effect when the params are absent.
+   */
   private openLoginDialogsFromTestModeQueryParams(): void {
     if (typeof window === 'undefined') {
       return;
@@ -97,6 +103,9 @@ export class App implements OnInit {
     if (params.get('adminLogin') === 'true') {
       this.adminAuthService.requestLogin();
     }
+    if (params.get('devBypassAdmin') === 'true') {
+      this.adminAuthService.devBypassLogin();
+    }
   }
 
   private setupAutoUpdates(): void {