feat(docs): replace vitepress with vuepress

* vitepress too limited

docs/src/.vuepress/theme/index.ts

@@ -0,0 +1,9 @@
+import { resolve } from 'path'
+
+export default {
+  name: 'vuepress-theme-local',
+  extends: '@vuepress/theme-default',
+  layouts: {
+    Layout: resolve(__dirname, 'layouts/default.vue'),
+  },
+}

docs/src/.vuepress/theme/layouts/default.vue

@@ -0,0 +1,16 @@
+<script>
+import 'virtual:windi.css'
+import '@braks/vue-flow/dist/style.css'
+import '@braks/vue-flow/dist/theme-default.css'
+import '../../assets/index.css'
+</script>
+<script setup>
+import ParentLayout from '@vuepress/theme-default/lib/client/layouts/Layout.vue'
+</script>
+<template>
+  <ParentLayout>
+    <template #page-bottom>
+      <div class="my-footer">This is my custom page footer</div>
+    </template>
+  </ParentLayout>
+</template>