fix: 404时标题为undefined

web/src/router/guard/page-title-guard.ts

@@ -6,7 +6,7 @@ import { useThemeStore } from '@/store'
 export function createPageTitleGuard(router: Router) {
   const themeStore = useThemeStore()
   router.afterEach((to) => {
-    const pageTitle = translateTitle(String(to.meta.title))
+    const pageTitle = typeof to.meta.title === 'string' ? translateTitle(to.meta.title) : '404'
     if (pageTitle) document.title = `${pageTitle} | ${themeStore.name}`
     else document.title = themeStore.name
   })