fix pylint errors

backend/requirements.txt

@@ -0,0 +1,84 @@
+alembic==1.18.4
+annotated-doc==0.0.4
+annotated-types==0.7.0
+anyio==4.12.1
+astroid==4.0.4
+autopep8==2.3.2
+brotli==1.2.0
+certifi==2026.2.25
+cffi==2.0.0
+charset-normalizer==3.4.4
+click==8.3.1
+coverage==7.13.4
+cryptography==46.0.5
+cssselect2==0.9.0
+dill==0.4.1
+dnspython==2.8.0
+email-validator==2.3.0
+fastapi==0.135.1
+fastapi-cli==0.0.24
+fastapi-cloud-cli==0.14.0
+fastar==0.8.0
+fonttools==4.61.1
+greenlet==3.3.2
+h11==0.16.0
+httpcore==1.0.9
+httptools==0.7.1
+httpx==0.28.1
+idna==3.11
+iniconfig==2.3.0
+isort==8.0.1
+Jinja2==3.1.6
+lxml==6.0.2
+Mako==1.3.10
+markdown-it-py==4.0.0
+MarkupSafe==3.0.3
+mccabe==0.7.0
+mdurl==0.1.2
+odfdo==3.21.0
+packaging==26.0
+pillow==12.1.1
+platformdirs==4.9.2
+pluggy==1.6.0
+prek==0.3.4
+psycopg2-binary==2.9.11
+pycodestyle==2.14.0
+pycparser==3.0
+pydantic==2.12.5
+pydantic-extra-types==2.11.0
+pydantic-settings==2.13.1
+pydantic_core==2.41.5
+pydyf==0.12.1
+Pygments==2.19.2
+PyJWT==2.11.0
+pylint==4.0.5
+pyphen==0.17.2
+pytest==9.0.2
+pytest-cov==7.0.0
+pytest-mock==3.15.1
+python-dotenv==1.2.2
+python-multipart==0.0.22
+PyYAML==6.0.3
+requests==2.32.5
+rich==14.3.3
+rich-toolkit==0.19.7
+rignore==0.7.6
+sentry-sdk==2.53.0
+shellingham==1.5.4
+SQLAlchemy==2.0.47
+sqlmodel==0.0.37
+starlette==0.52.1
+tinycss2==1.5.1
+tinyhtml5==2.0.0
+tomlkit==0.14.0
+typer==0.24.1
+typing-inspection==0.4.2
+typing_extensions==4.15.0
+urllib3==2.6.3
+uvicorn==0.41.0
+uvloop==0.22.1
+watchfiles==1.1.1
+weasyprint==68.1
+webencodings==0.5.1
+websockets==16.0
+zopfli==0.4.1