Fix mode parameter serialization error in Ollama chat API

• Use mode.value for API requests
• Add debug logging in aquery_llm

lightrag/api/routers/ollama_api.py

@@ -499,7 +499,7 @@ class OllamaAPI:
                 prompt_tokens = estimate_tokens(cleaned_query)
 
                 param_dict = {
-                    "mode": mode,
+                    "mode": mode.value,
                     "stream": request.stream,
                     "only_need_context": only_need_context,
                     "conversation_history": conversation_history,

lightrag/lightrag.py

@@ -2322,6 +2322,8 @@ class LightRAG:
         Returns:
             dict[str, Any]: Complete response with structured data and LLM response.
         """
+        logger.debug(f"[aquery_llm] Query param: {param}")
+
         global_config = asdict(self)
 
         try: