ci: add ruff linting and mypy type checking

Add ruff and mypy to dev dependencies with configuration in pyproject.toml.
Add a lint CI job that runs ruff check, ruff format --check, and mypy.
Auto-fix import sorting and formatting across the codebase. Exclude
alembic/versions from linting (auto-generated migrations). Ignore B008
(FastAPI Depends pattern) and RUF001 (unicode in user-facing strings).

21 ruff lint errors and 50 mypy errors remain for manual review.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

app/services/domains/users/application.py

@@ -39,9 +39,7 @@ async def get_user_by_id(db_session: AsyncSession, user_id: int) -> User | None:
 
 
 async def get_user_by_email(db_session: AsyncSession, email: str) -> User | None:
-    result = await db_session.execute(
-        select(User).where(User.email == normalize_email(email))
-    )
+    result = await db_session.execute(select(User).where(User.email == normalize_email(email)))
     return result.scalar_one_or_none()
 
 
@@ -95,4 +93,3 @@ async def set_user_password_hash(
     await db_session.commit()
     await db_session.refresh(user)
     return user
-