Fixes: 1) Correct default value in `recently_viewed` property to handle cache miss;
Extra: 1) Inline simplification of serializer logic for recently viewed products.
Fixes: 1) Correct logic in `get_recently_viewed` method to properly handle `recently_viewed` items.
Extra: 1) Add missing import for `drf_spectacular.utils.extend_schema_field`; 2) Update method docstring for clarity; 3) Adjust typing in `get_recently_viewed` to use `List[Dict[str, Any]]`.
Fixes: 1) Fix `resolve_recently_viewed` to handle empty UUIDs and avoid breaking queries.
Extra: Refactor imports in `graphene/object_types.py` and `serializers.py` for better clarity; Adjust minor formatting in `TokenObtainSerializer`.
