Navigate to root path after successful login via login/:code route in AuthGuard.

frontend/src/app/guards/auth.guard.ts

@@ -27,6 +27,9 @@ export class AuthGuard implements CanActivate {
       return this.authService.login(code).pipe(
         switchMap(() => {
           const result = this.canActivateInternal(route, state);
+          if (route.routeConfig?.path === 'login/:code') {
+            this.router.navigateByUrl('/', {replaceUrl: true}).then();
+          }
           return isObservable(result) ? result : result instanceof Promise ? from(result) : of(result);
         }),
         catchError(() => of(this.router.createUrlTree(['/'])))