feat: new frontend demo

apps/new-frontend/src/views/NotFoundView.vue

@@ -0,0 +1,20 @@
+<script setup lang="ts">
+import { useRouter } from '@/app/router'
+import { buttonBase, buttonTone } from '@/components/ui'
+
+const router = useRouter()
+</script>
+
+<template>
+  <section class="rounded-lg border border-zinc-200 bg-white p-8 text-center shadow-sm">
+    <h2 class="text-xl font-semibold">页面不存在</h2>
+    <p class="mt-2 text-sm text-zinc-500">当前地址没有对应的新前端页面。</p>
+    <button
+      :class="[buttonBase, buttonTone.primary, 'mt-5']"
+      type="button"
+      @click="router.navigate('/dashboard')"
+    >
+      返回仪表盘
+    </button>
+  </section>
+</template>