fix：移除冗余代码，丰富replyer log记录，表达方式改为replyer模型

src/learners/expression_learner.py

@@ -31,11 +31,9 @@ if TYPE_CHECKING:
 logger = get_logger("expressor")
 
 express_learn_model = LLMServiceClient(
-    task_name="utils", request_type="expression.learner"
+    task_name="replyer", request_type="expression.learner"
 )
-summary_model = LLMServiceClient(task_name="utils", request_type="expression.summary")
-check_model = LLMServiceClient(task_name="utils", request_type="expression.check")
-
+summary_model = LLMServiceClient(task_name="replyer", request_type="expression.summary")
 
 def register_expression_hook_specs(registry: HookSpecRegistry) -> List[HookSpec]:
     """注册表达方式系统内置 Hook 规格。