Add ruff linter/formatter for Python

- Add ruff as dev dependency
- Configure ruff in pyproject.toml with strict 88-char line limit
- Ignore B008 (FastAPI Depends pattern is standard)
- Allow longer lines in tests for readability
- Fix all lint issues in source files
- Add Makefile targets: lint-backend, format-backend, fix-backend

backend/tests/conftest.py

@@ -7,28 +7,28 @@ os.environ.setdefault("SECRET_KEY", "test-secret-key-for-testing-only")
 import pytest
 from httpx import ASGITransport, AsyncClient
 from sqlalchemy import select
-from sqlalchemy.ext.asyncio import create_async_engine, async_sessionmaker, AsyncSession
+from sqlalchemy.ext.asyncio import AsyncSession, async_sessionmaker, create_async_engine
 
+from auth import get_password_hash
 from database import Base, get_db
 from main import app
-from models import User, Role, Permission, ROLE_DEFINITIONS, ROLE_REGULAR, ROLE_ADMIN
-from auth import get_password_hash
+from models import ROLE_ADMIN, ROLE_DEFINITIONS, ROLE_REGULAR, Role, User
 from tests.helpers import unique_email
 
 TEST_DATABASE_URL = os.getenv(
     "TEST_DATABASE_URL",
-    "postgresql+asyncpg://postgres:postgres@localhost:5432/arbret_test"
+    "postgresql+asyncpg://postgres:postgres@localhost:5432/arbret_test",
 )
 
 
 class ClientFactory:
     """Factory for creating httpx clients with optional cookies."""
-    
+
     def __init__(self, transport, base_url, session_factory):
         self._transport = transport
         self._base_url = base_url
         self._session_factory = session_factory
-    
+
     @asynccontextmanager
     async def create(self, cookies: dict | None = None):
         """Create a new client, optionally with cookies set."""
@@ -38,15 +38,15 @@ class ClientFactory:
             cookies=cookies or {},
         ) as client:
             yield client
-    
+
     async def request(self, method: str, url: str, **kwargs):
         """Make a one-off request without cookies."""
         async with self.create() as client:
             return await client.request(method, url, **kwargs)
-    
+
     async def get(self, url: str, **kwargs):
         return await self.request("GET", url, **kwargs)
-    
+
     async def post(self, url: str, **kwargs):
         return await self.request("POST", url, **kwargs)
 
@@ -64,16 +64,16 @@ async def setup_roles(db: AsyncSession) -> dict[str, Role]:
         # Check if role exists
         result = await db.execute(select(Role).where(Role.name == role_name))
         role = result.scalar_one_or_none()
-        
+
         if not role:
             role = Role(name=role_name, description=config["description"])
             db.add(role)
             await db.flush()
-        
+
         # Set permissions
         await role.set_permissions(db, config["permissions"])
         roles[role_name] = role
-    
+
     await db.commit()
     return roles
 
@@ -91,9 +91,11 @@ async def create_user_with_roles(
         result = await db.execute(select(Role).where(Role.name == role_name))
         role = result.scalar_one_or_none()
         if not role:
-            raise ValueError(f"Role '{role_name}' not found. Did you run setup_roles()?")
+            raise ValueError(
+                f"Role '{role_name}' not found. Did you run setup_roles()?"
+            )
         roles.append(role)
-    
+
     user = User(
         email=email,
         hashed_password=get_password_hash(password),
@@ -110,27 +112,27 @@ async def client_factory():
     """Fixture that provides a factory for creating clients."""
     engine = create_async_engine(TEST_DATABASE_URL)
     session_factory = async_sessionmaker(engine, expire_on_commit=False)
-    
+
     # Create tables
     async with engine.begin() as conn:
         await conn.run_sync(Base.metadata.drop_all)
         await conn.run_sync(Base.metadata.create_all)
-    
+
     # Setup roles
     async with session_factory() as db:
         await setup_roles(db)
-    
+
     async def override_get_db():
         async with session_factory() as session:
             yield session
-    
+
     app.dependency_overrides[get_db] = override_get_db
-    
+
     transport = ASGITransport(app=app)
     factory = ClientFactory(transport, "http://test", session_factory)
-    
+
     yield factory
-    
+
     app.dependency_overrides.clear()
     await engine.dispose()
 
@@ -147,17 +149,17 @@ async def regular_user(client_factory):
     """Create a regular user and return their credentials and cookies."""
     email = unique_email("regular")
     password = "password123"
-    
+
     async with client_factory.get_db_session() as db:
         user = await create_user_with_roles(db, email, password, [ROLE_REGULAR])
         user_id = user.id
-    
+
     # Login to get cookies
     response = await client_factory.post(
         "/api/auth/login",
         json={"email": email, "password": password},
     )
-    
+
     return {
         "email": email,
         "password": password,
@@ -172,17 +174,17 @@ async def alt_regular_user(client_factory):
     """Create a second regular user for tests needing multiple users."""
     email = unique_email("alt_regular")
     password = "password123"
-    
+
     async with client_factory.get_db_session() as db:
         user = await create_user_with_roles(db, email, password, [ROLE_REGULAR])
         user_id = user.id
-    
+
     # Login to get cookies
     response = await client_factory.post(
         "/api/auth/login",
         json={"email": email, "password": password},
     )
-    
+
     return {
         "email": email,
         "password": password,
@@ -197,16 +199,16 @@ async def admin_user(client_factory):
     """Create an admin user and return their credentials and cookies."""
     email = unique_email("admin")
     password = "password123"
-    
+
     async with client_factory.get_db_session() as db:
         await create_user_with_roles(db, email, password, [ROLE_ADMIN])
-    
+
     # Login to get cookies
     response = await client_factory.post(
         "/api/auth/login",
         json={"email": email, "password": password},
     )
-    
+
     return {
         "email": email,
         "password": password,
@@ -220,16 +222,16 @@ async def user_no_roles(client_factory):
     """Create a user with NO roles and return their credentials and cookies."""
     email = unique_email("noroles")
     password = "password123"
-    
+
     async with client_factory.get_db_session() as db:
         await create_user_with_roles(db, email, password, [])
-    
+
     # Login to get cookies
     response = await client_factory.post(
         "/api/auth/login",
         json={"email": email, "password": password},
     )
-    
+
     return {
         "email": email,
         "password": password,