Add tests for auth dependencies and security utilities

Introduced unit tests for `get_current_user`, `get_current_active_user`, and security functions like token creation and decoding. Also refactored imports for consistency and cleaned up unused or misplaced code to improve maintainability.

backend/app/auth/dependencies.py

@@ -3,13 +3,13 @@ from fastapi.security import OAuth2PasswordBearer
 from jose import JWTError, jwt
 from sqlalchemy.ext.asyncio import AsyncSession
 
-from auth.security import SECRET_KEY, ALGORITHM
 from app.core.database import get_db
-from models.user import User
-from app.schemas.token import TokenData
+from auth.security import SECRET_KEY, ALGORITHM
+from app.models.user import User
 
 oauth2_scheme = OAuth2PasswordBearer(tokenUrl="auth/token")
 
+
 async def get_current_user(
         token: str = Depends(oauth2_scheme),
         db: AsyncSession = Depends(get_db)
@@ -37,9 +37,10 @@ async def get_current_user(
 
     return user
 
+
 async def get_current_active_user(
         current_user: User = Depends(get_current_user),
 ):
     if not current_user.is_active:
         raise HTTPException(status_code=400, detail="Inactive user")
-    return current_user
+    return current_user

backend/app/auth/security.py

@@ -5,7 +5,7 @@ from uuid import uuid4
 from jose import jwt, JWTError
 from passlib.context import CryptContext
 from app.core.config import settings
-from .token import TokenPayload, TokenResponse
+from app.schemas.token import TokenPayload, TokenResponse
 
 # Configuration
 SECRET_KEY = settings.SECRET_KEY