feat: Windows 服务 安装，启动，停止 功能

scientific_surfing/subscription_manager.py

@@ -3,6 +3,7 @@ Subscription management module for scientific-surfing.
 Handles subscription operations with persistent storage.
 """
 
+from datetime import datetime
 import requests
 from scientific_surfing.storage import StorageManager
 
@@ -78,7 +79,6 @@ class SubscriptionManager:
 
             # Update subscription metadata
             subscription.last_refresh = datetime.now()
-            subscription.file_path = str(file_path)
             subscription.file_size = len(response.text)
             subscription.status_code = response.status_code
             subscription.content_hash = hash(response.text)