feat: add reasoning_effort config to enable LLM thinking mode

nanobot/providers/litellm_provider.py

@@ -178,6 +178,7 @@ class LiteLLMProvider(LLMProvider):
         model: str | None = None,
         max_tokens: int = 4096,
         temperature: float = 0.7,
+        reasoning_effort: str | None = None,
     ) -> LLMResponse:
         """
         Send a chat completion request via LiteLLM.
@@ -224,6 +225,10 @@ class LiteLLMProvider(LLMProvider):
         if self.extra_headers:
             kwargs["extra_headers"] = self.extra_headers
         
+        if reasoning_effort:
+            kwargs["reasoning_effort"] = reasoning_effort
+            kwargs["drop_params"] = True
+        
         if tools:
             kwargs["tools"] = tools
             kwargs["tool_choice"] = "auto"