feat: 集成简易暗黑模式

src/layout/components/header/index.vue

@@ -4,6 +4,7 @@
     <BreadCrumb ml-15 />
   </div>
   <div ml-auto flex items-center>
+    <ThemeMode />
     <GithubSite />
     <FullScreen />
     <UserAvatar />
@@ -16,4 +17,5 @@ import MenuCollapse from './components/MenuCollapse.vue'
 import FullScreen from './components/FullScreen.vue'
 import UserAvatar from './components/UserAvatar.vue'
 import GithubSite from './components/GithubSite.vue'
+import ThemeMode from './components/ThemeMode.vue'
 </script>