fix: replace passlib with direct bcrypt to fix password hashing crash

passlib 1.7.4 is incompatible with bcrypt>=4.1, causing a ValueError
during internal bug detection. Using bcrypt directly avoids this.

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

server/auth.py

@@ -8,10 +8,10 @@ import secrets
 from datetime import datetime, timedelta, timezone
 from typing import Optional
 
+import bcrypt
 from fastapi import Depends, HTTPException, status
 from fastapi.security import HTTPAuthorizationCredentials, HTTPBearer
 from jose import JWTError, jwt
-from passlib.context import CryptContext
 
 logger = logging.getLogger(__name__)
 
@@ -19,18 +19,17 @@ JWT_SECRET = os.getenv("JWT_SECRET") or secrets.token_urlsafe(32)
 JWT_ALGORITHM = "HS256"
 JWT_EXPIRE_HOURS = 24
 
-pwd_context = CryptContext(schemes=["bcrypt"], deprecated="auto")
 bearer_scheme = HTTPBearer(auto_error=False)
 
 
 def hash_password(password: str) -> str:
     """Hash a plain-text password with bcrypt."""
-    return pwd_context.hash(password)
+    return bcrypt.hashpw(password.encode("utf-8"), bcrypt.gensalt()).decode("utf-8")
 
 
 def verify_password(plain: str, hashed: str) -> bool:
     """Verify a plain-text password against its bcrypt hash."""
-    return pwd_context.verify(plain, hashed)
+    return bcrypt.checkpw(plain.encode("utf-8"), hashed.encode("utf-8"))
 
 
 def create_access_token(subject: str) -> str: