fix: 修复课程详情页标题显示问题

动态设置页面标题为课程标题或默认值

@@ -351,7 +351,7 @@ import { checkinTaskAPI } from '@/api/checkin';
 
 const $route = useRoute();
 const $router = useRouter();
-useTitle($route.meta.title);
+useTitle(`${course.value.title || '课程详情'}`);
 
 const route = useRoute()
 const router = useRouter()