feat: configure Dify API key for AI chat

Retrieved from Dify app API access page

Co-authored-by: Sisyphus <clio-agent@sisyphuslabs.ai>

cfc-backend/src/main/resources/application.yml

@@ -70,7 +70,7 @@ wechat:
 
 dify:
   base-url: http://dify.bianwoyou.cn/v1
-  api-key: app-your-api-key-here
+  api-key: app-rtNSAHG2NFzRsXCGkeZlVNR9
 
 logging:
   level: