Fixes: 1) Remove unused imports for serializers and inline_serializer from drf_spectacular.utils.
Extra: Refactor and simplify code by replacing inline schema definitions with centralized schema references (TOKEN_OBTAIN_SCHEMA, TOKEN_REFRESH_SCHEMA, TOKEN_VERIFY_SCHEMA) and removing redundant response examples.
Fixes: 1) Adjust import order in `core/models.py` for better consistency;
Extra: Refactor formatting for better readability in `core/models.py`; Update `pyproject.toml` version to 2.6.2; Update compiled translation file `cs_CZ/LC_MESSAGES/django.mo`.