refactor: reorganize backend module boundaries

app/application/notification.py

@@ -0,0 +1,34 @@
+from typing import Optional
+
+from app.runtime.extensions.service_registry import ServiceBaseHelper
+from app.schemas import NotificationConf, ServiceInfo
+from app.schemas.types import ModuleType, SystemConfigKey
+
+
+class NotificationHelper(ServiceBaseHelper[NotificationConf]):
+    """提供按持久化配置发现通知服务的能力。"""
+
+    def __init__(self):
+        """绑定通知配置和通知模块类型。"""
+        super().__init__(
+            config_key=SystemConfigKey.Notifications,
+            conf_type=NotificationConf,
+            module_type=ModuleType.Notification,
+        )
+
+    def is_notification(
+        self,
+        service_type: Optional[str] = None,
+        service: Optional[ServiceInfo] = None,
+        name: Optional[str] = None,
+    ) -> bool:
+        """
+        判断通知服务是否属于指定类型。
+
+        :param service_type: 消息通知服务的类型名称
+        :param service: 要判断的服务信息
+        :param name: 未传入服务信息时用于查询的服务名称
+        :return: 服务存在且类型匹配时返回 True
+        """
+        service = service or self.get_service(name=name)
+        return bool(service and service.type == service_type)