internal: incomplete vault systems behind feature flag (#2340)

packages/ui-services/src/Abstract/AbstractUIServiceInterface.ts

@@ -0,0 +1,7 @@
+import { ApplicationEvent, ServiceInterface } from '@standardnotes/services'
+
+export interface AbstractUIServiceInterface<EventName = string, EventData = unknown>
+  extends ServiceInterface<EventName, EventData> {
+  onAppStart(): Promise<void>
+  onAppEvent(event: ApplicationEvent): Promise<void>
+}