移除示例项目初始化并修复前后端稳定性问题

frontend/src/main.ts

@@ -15,12 +15,15 @@ import { useStudyStore } from "./store/study";
 const app = createApp(App);
 const pinia = createPinia();
 app.use(pinia);
-app.use(router);
 dayjs.locale("zh-cn");
 app.use(ElementPlus, { locale: zhCn });
 
 // 初始化项目上下文
 const studyStore = useStudyStore();
 studyStore.loadCurrentStudy();
+await studyStore.rehydrateStudyForLastUser();
+
+app.use(router);
+await router.isReady();
 
 app.mount("#app");