linter + новые таски

backend/src/core/task_manager/cleanup.py

@@ -5,7 +5,6 @@
 # @LAYER: Core
 # @RELATION: Uses TaskPersistenceService and TaskLogPersistenceService to delete old tasks and logs.
 
-from datetime import datetime, timedelta
 from typing import List
 from .persistence import TaskPersistenceService, TaskLogPersistenceService
 from ..logger import logger, belief_scope