fix: skills variable init + ChatPage show all published apps + populate skill content

backend/python/app/api/chat.py

@@ -875,6 +875,8 @@ async def send_message(
     ai_content = ""
 
     ai_model = None
+    skills = []  # 初始化避免UnboundLocalError
+    agents = []  # 初始化避免UnboundLocalError
     if model_id:
         ai_model = db.query(AIModel).filter(AIModel.id == model_id).first()