style: apply black and isort formatting across entire codebase

- Standardize quote style (single to double quotes)
- Reorder and group imports alphabetically
- Fix line breaks and indentation for consistency
- Apply PEP 8 formatting standards

Also updated Makefile to exclude both venv and .venv from code quality checks.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

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

app/services/auth_service.py

@@ -13,15 +13,12 @@ from typing import Any, Dict, Optional
 
 from sqlalchemy.orm import Session
 
-from app.exceptions import (
-    UserAlreadyExistsException,
-    InvalidCredentialsException,
-    UserNotActiveException,
-    ValidationException,
-)
+from app.exceptions import (InvalidCredentialsException,
+                            UserAlreadyExistsException, UserNotActiveException,
+                            ValidationException)
 from middleware.auth import AuthManager
-from models.schema.auth import UserLogin, UserRegister
 from models.database.user import User
+from models.schema.auth import UserLogin, UserRegister
 
 logger = logging.getLogger(__name__)
 
@@ -51,11 +48,15 @@ class AuthService:
         try:
             # Check if email already exists
             if self._email_exists(db, user_data.email):
-                raise UserAlreadyExistsException("Email already registered", field="email")
+                raise UserAlreadyExistsException(
+                    "Email already registered", field="email"
+                )
 
             # Check if username already exists
             if self._username_exists(db, user_data.username):
-                raise UserAlreadyExistsException("Username already taken", field="username")
+                raise UserAlreadyExistsException(
+                    "Username already taken", field="username"
+                )
 
             # Hash password and create user
             hashed_password = self.auth_manager.hash_password(user_data.password)
@@ -182,7 +183,9 @@ class AuthService:
             Dictionary with access_token, token_type, and expires_in
         """
         from datetime import datetime, timedelta, timezone
+
         from jose import jwt
+
         from app.core.config import settings
 
         try:
@@ -217,6 +220,5 @@ class AuthService:
         return db.query(User).filter(User.username == username).first() is not None
 
 
-
 # Create service instance following the same pattern as other services
 auth_service = AuthService()