docs: explain navigation, search and content components

app/components/RingProgress.vue

@@ -1,4 +1,5 @@
 <script>
+// 环形进度通过圆周长和描边偏移表达百分比，绘制时把输入限制在 0–100 范围。
 import "~/assets/styles/RingProgress.CVwR7il5.css";
 import { toDisplayString } from "vue";
 import { createCommentVNode } from "vue";