Fix: Add missing Optional import in crossswitch router

src/api/routers/crossswitch.py

@@ -1,6 +1,7 @@
 """
 Cross-switch router for camera-to-monitor routing operations
 """
+from typing import Optional
 from fastapi import APIRouter, Depends, status, HTTPException, Query, Request
 from sqlalchemy.ext.asyncio import AsyncSession
 import structlog
@@ -275,8 +276,6 @@ async def get_routing_history(
     - Investigate when a camera was last displayed on a monitor
     - Track operator actions
     """
-    from typing import Optional  # Import for type hints
-
     crossswitch_service = CrossSwitchService(db)
 
     logger.info("get_routing_history_request",