feat-dev: add U2F iframe for desktop client authentication (#2236)

packages/web/src/javascripts/Application/Application.ts

@@ -430,6 +430,14 @@ export class WebApplication extends SNApplication implements WebApplicationInter
     this.getViewControllerManager().accountMenuController.setShow(false)
   }
 
+  /**
+   * Full U2F clients are only web browser clients. They support adding and removing keys as well as authentication.
+   * The desktop and mobile clients cannot support adding keys.
+   */
+  get isFullU2FClient(): boolean {
+    return this.environment === Environment.Web
+  }
+
   geDefaultEditorIdentifier(currentTag?: SNTag): EditorIdentifier {
     return (
       currentTag?.preferences?.editorIdentifier ||