replace api key with placeholder

config.py

@@ -2,7 +2,7 @@
 import os
 
 # DeepSeek V4 Flash
-LLM_API_KEY  = os.getenv("LLM_API_KEY", "sk-5fe08380dd6048348f165c82e120dd1d")
+LLM_API_KEY  = os.getenv("LLM_API_KEY", "你的APIKEY")
 LLM_BASE_URL = os.getenv("LLM_BASE_URL", "https://api.deepseek.com/v1")
 LLM_MODEL    = os.getenv("LLM_MODEL", "deepseek-v4-flash")