debug: add JWT validation logging to diagnose 401 errors

backend/auth.py

@@ -64,11 +64,16 @@ async def get_current_user(credentials = Depends(security)):
     Returns TokenData with user_id, username, role.
     """
     token = credentials.credentials
+    import logging
+    log = logging.getLogger("ainventory")
+    log.debug(f"[AUTH] Validating token (first 20 chars): {token[:20] if token else 'None'}")
+    log.debug(f"[AUTH] Using SECRET_KEY (first 10 chars): {SECRET_KEY[:10] if SECRET_KEY else 'None'}")
     try:
         payload = jwt.decode(token, SECRET_KEY, algorithms=[ALGORITHM])
         user_id: int = payload.get("sub")
         username: str = payload.get("username")
         role: str = payload.get("role")
+        log.debug(f"[AUTH] Token valid — user_id={user_id}, username={username}, role={role}")
 
         if user_id is None or username is None:
             raise HTTPException(
@@ -81,7 +86,8 @@ async def get_current_user(credentials = Depends(security)):
             role=role,
             exp=datetime.fromtimestamp(payload.get("exp"), tz=timezone.utc)
         )
-    except JWTError:
+    except JWTError as e:
+        log.error(f"[AUTH] JWTError: {type(e).__name__}: {str(e)}")
         raise HTTPException(
             status_code=status.HTTP_401_UNAUTHORIZED,
             detail="Invalid authentication credentials",