feat：统一replyer在是否多模态下的表现，提高一致性和通用性，新增模型visual参数

src/llm_models/request_snapshot.py

@@ -228,6 +228,7 @@ def serialize_model_info_snapshot(model_info: ModelInfo) -> dict[str, Any]:
         "model_identifier": model_info.model_identifier,
         "name": model_info.name,
         "temperature": model_info.temperature,
+        "visual": model_info.visual,
     }
 
 
@@ -244,6 +245,7 @@ def deserialize_model_info_snapshot(raw_model_info: Any) -> ModelInfo:
         model_identifier=str(raw_model_info.get("model_identifier") or ""),
         name=str(raw_model_info.get("name") or ""),
         temperature=raw_model_info.get("temperature"),
+        visual=bool(raw_model_info.get("visual", False)),
     )