diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index e448773b..f2b83f9f 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -14,7 +14,7 @@ jobs:
       - uses: actions/setup-python@v5
         with:
           python-version: "3.12"
-      - run: pip install ruff mypy
+      - run: pip install ruff==0.16.6 mypy==2.3.1
       - run: ruff check backend/
       - run: ruff format --check backend/
 
@@ -27,8 +27,12 @@ jobs:
           python-version: "3.12"
           cache: pip
       - run: pip install -r backend/requirements.txt
-      - run: pip install pytest pytest-asyncio httpx
+      - run: pip install pytest pytest-asyncio httpx aiosqlite
       - run: pytest tests/ -v
+        working-directory: backend
+        env:
+          DATABASE_URL: sqlite+aiosqlite:///test.db
+          JWT_SECRET_KEY: ci-test-secret-key
 
   docker-build:
     runs-on: ubuntu-latest
diff --git a/backend/dwf/api/routers/auth.py b/backend/dwf/api/routers/auth.py
index 5c2c0972..87ebc151 100644
--- a/backend/dwf/api/routers/auth.py
+++ b/backend/dwf/api/routers/auth.py
@@ -3,13 +3,13 @@
 from sqlalchemy.ext.asyncio import AsyncSession
 
 from dwf.api.deps import get_db, get_settings
-from dwf.services.auth_service import AuthService
 from dwf.domain.models.user import (
-    RegisterRequest,
     LoginRequest,
-    TokenResponse,
     RefreshRequest,
+    RegisterRequest,
+    TokenResponse,
 )
+from dwf.services.auth_service import AuthService
 from dwf.settings import Settings
 
 router = APIRouter(prefix="/auth", tags=["auth"])
diff --git a/backend/dwf/infrastructure/database/models/__init__.py b/backend/dwf/infrastructure/database/models/__init__.py
index 8c4bc83c..09d550a9 100644
--- a/backend/dwf/infrastructure/database/models/__init__.py
+++ b/backend/dwf/infrastructure/database/models/__init__.py
@@ -1,4 +1,4 @@
-from .Base import Base
+from .base import Base
 from .user import User
 from .workflow import Workflow
 
diff --git a/backend/dwf/infrastructure/database/models/Base.py b/backend/dwf/infrastructure/database/models/base.py
similarity index 100%
rename from backend/dwf/infrastructure/database/models/Base.py
rename to backend/dwf/infrastructure/database/models/base.py
diff --git a/backend/dwf/infrastructure/database/models/user.py b/backend/dwf/infrastructure/database/models/user.py
index 3b19ed85..4ead3502 100644
--- a/backend/dwf/infrastructure/database/models/user.py
+++ b/backend/dwf/infrastructure/database/models/user.py
@@ -5,7 +5,7 @@
 from sqlalchemy.orm import Mapped, mapped_column
 from sqlalchemy.sql import func
 
-from .Base import Base
+from .base import Base
 
 
 class User(Base):
diff --git a/backend/dwf/infrastructure/database/models/workflow.py b/backend/dwf/infrastructure/database/models/workflow.py
index a484caf2..4388eda3 100644
--- a/backend/dwf/infrastructure/database/models/workflow.py
+++ b/backend/dwf/infrastructure/database/models/workflow.py
@@ -5,7 +5,7 @@
 from sqlalchemy.orm import Mapped, mapped_column
 from sqlalchemy.sql import func
 
-from .Base import Base
+from .base import Base
 
 
 class Workflow(Base):
diff --git a/backend/dwf/main.py b/backend/dwf/main.py
index 7e47ad80..1ef5ce5a 100644
--- a/backend/dwf/main.py
+++ b/backend/dwf/main.py
@@ -37,8 +37,8 @@ def create_app(settings: Settings | None = None) -> FastAPI:
     )
     app.state.settings = settings
 
-    from dwf.api.routers.health import router as health_router
     from dwf.api.routers.auth import router as auth_router
+    from dwf.api.routers.health import router as health_router
     from dwf.api.routers.workflows import router as workflows_router
 
     app.include_router(health_router)
diff --git a/backend/dwf/settings.py b/backend/dwf/settings.py
index 5d271f27..97a49303 100644
--- a/backend/dwf/settings.py
+++ b/backend/dwf/settings.py
@@ -13,6 +13,3 @@ class Settings(BaseSettings):
         env_file_encoding="utf-8",
         case_sensitive=False,
     )
-
-
-settings = Settings()
diff --git a/backend/requirements.txt b/backend/requirements.txt
index b8b3510b..bac7f768 100644
--- a/backend/requirements.txt
+++ b/backend/requirements.txt
@@ -1,58 +1,94 @@
+aiosqlite==0.22.1
 alembic==1.19.1
 amqp==5.3.1
 annotated-doc==0.0.5
 annotated-types==0.8.0
 anyio==4.14.2
+argon2-cffi==25.1.0
+argon2-cffi-bindings==26.1.0
+ast_serialize==0.11.0
+asyncpg==0.31.0
 bcrypt==5.0.0
 billiard==4.2.4
 celery==5.6.3
 certifi==2026.7.22
+cffi==2.1.1
+cfgv==3.5.0
+charset-normalizer==3.5.1
 click==8.4.2
 click-didyoumean==0.3.1
 click-plugins==1.1.1.2
 click-repl==0.3.0
+cryptography==50.0.1
+distlib==0.4.3
 distro==1.9.0
 dnspython==2.8.0
 ecdsa==0.19.2
 email-validator==2.3.0
 fastapi==0.141.1
-greenlet==3.5.5
+filelock==3.32.5
+google-auth==2.57.1
 google-genai==1.52.0
+greenlet==3.5.5
 h11==0.16.0
 httpcore==1.0.9
+httptools==0.8.0
 httpx==0.28.1
+identify==2.6.19
 idna==3.18
 iniconfig==2.3.0
 jiter==0.16.0
 kombu==5.6.2
+librt==0.15.0
 Mako==1.4.1
 MarkupSafe==3.0.3
+mypy==2.3.1
+mypy_extensions==1.1.0
+nodeenv==1.10.0
 openai==2.53.0
 packaging==26.3
 passlib==1.7.4
+pathspec==1.1.1
+platformdirs==4.11.7
 pluggy==1.6.0
+pre_commit==4.6.2
 prompt_toolkit==3.0.53
 psycopg2-binary==2.9.12
 pyasn1==0.6.4
+pyasn1_modules==0.4.2
+pycparser==3.0
 pydantic==2.13.4
 pydantic-settings==2.15.0
 pydantic_core==2.46.4
 Pygments==2.20.0
+PyJWT==2.14.0
 pytest==9.1.1
+pytest-asyncio==1.4.0
 python-dateutil==2.9.0.post0
+python-discovery==1.6.0
 python-dotenv==1.2.2
 python-jose==3.5.0
+PyYAML==6.0.3
 redis==8.1.0
+requests==2.34.2
 rsa==4.9.1
+ruff==0.16.6
 six==1.17.0
 sniffio==1.3.1
 SQLAlchemy==2.0.51
 starlette==1.6.0
+structlog==26.1.0
+tenacity==9.1.4
 tqdm==4.70.0
 typing-inspection==0.4.3
 typing_extensions==4.16.0
 tzdata==2026.3
 tzlocal==5.4.4
+urllib3==2.7.0
 uvicorn==0.52.1
+uvloop==0.22.1
 vine==5.1.0
+virtualenv==21.7.8
+watchfiles==1.2.0
 wcwidth==0.8.2
+websockets==15.0.1
diff --git a/backend/test.db b/backend/test.db
index 8bb9c17d..129598f4 100644
Binary files a/backend/test.db and b/backend/test.db differ
diff --git a/backend/tests/conftest.py b/backend/tests/conftest.py
index 526c564d..8c31c8ef 100644
--- a/backend/tests/conftest.py
+++ b/backend/tests/conftest.py
@@ -2,9 +2,9 @@
 from httpx import ASGITransport, AsyncClient
 from sqlalchemy.ext.asyncio import AsyncSession, async_sessionmaker, create_async_engine
 
+from dwf.api.deps import get_db
 from dwf.infrastructure.database.models import Base
 from dwf.main import create_app
-from dwf.api.deps import get_db
 from dwf.settings import Settings
 
 TEST_DATABASE_URL = "sqlite+aiosqlite:///test.db"