refactor backend module architecture

app/sdk/services.py

@@ -0,0 +1,27 @@
+"""插件可使用的宿主服务发现与运行时门面。"""
+
+from app.extensions.service_registry import ServiceBaseHelper, ServiceConfigHelper
+from app.platform.runtime import SystemHelper
+from app.services.downloader import DownloaderHelper
+from app.services.filter import RuleHelper
+from app.services.mediaserver import (
+    MediaServerIdentityHelper,
+    MediaServerHelper,
+    MusicMediaServerHelper,
+)
+from app.services.storage import StorageHelper
+from app.services.notification import NotificationHelper
+
+
+__all__ = [
+    "DownloaderHelper",
+    "MediaServerHelper",
+    "MediaServerIdentityHelper",
+    "MusicMediaServerHelper",
+    "NotificationHelper",
+    "RuleHelper",
+    "ServiceBaseHelper",
+    "ServiceConfigHelper",
+    "StorageHelper",
+    "SystemHelper",
+]