feat(web): add accepting subscription invites from UI

packages/ui-services/src/Toast/ToastService.ts

@@ -0,0 +1,12 @@
+import { addToast, ToastType } from '@standardnotes/toast'
+
+import { ToastServiceInterface } from './ToastServiceInterface'
+
+export class ToastService implements ToastServiceInterface {
+  showToast(type: ToastType, message: string): void {
+    addToast({
+      type: type,
+      message,
+    })
+  }
+}

packages/ui-services/src/Toast/ToastServiceInterface.ts

@@ -0,0 +1,5 @@
+import { ToastType } from '@standardnotes/toast'
+
+export interface ToastServiceInterface {
+  showToast(type: ToastType, message: string): void
+}