fix: replace passlib with direct bcrypt for bcrypt 5.0 compatibility

backend/app/auth.py

@@ -2,7 +2,7 @@
 from datetime import datetime, timedelta, timezone
 from typing import Optional
 from jose import JWTError, jwt
-from passlib.context import CryptContext
+import bcrypt
 from fastapi import Depends, HTTPException, status, Request
 from sqlalchemy.ext.asyncio import AsyncSession
 from sqlalchemy import select
@@ -12,17 +12,16 @@ from app.models.admin_user import AdminUser
 
 
 settings = get_settings()
-pwd_context = CryptContext(schemes=["bcrypt"], deprecated="auto")
 
 
 def verify_password(plain_password: str, hashed_password: str) -> bool:
     """Verify a plain password against a hash."""
-    return pwd_context.verify(plain_password, hashed_password)
+    return bcrypt.checkpw(plain_password.encode(), hashed_password.encode())
 
 
 def get_password_hash(password: str) -> str:
     """Hash a password using bcrypt."""
-    return pwd_context.hash(password)
+    return bcrypt.hashpw(password.encode(), bcrypt.gensalt()).decode()
 
 
 def create_access_token(data: dict, expires_delta: timedelta | None = None) -> str: