feat: use nuxt 4 structure

app/pages/[...all].vue

@@ -0,0 +1,17 @@
+<script setup lang="ts">
+const router = useRouter()
+</script>
+
+<template>
+  <main p="x4 y10" text="center teal-700 dark:gray-200">
+    <div text-4xl>
+      <div i-carbon-warning inline-block />
+    </div>
+    <div>Not found</div>
+    <div>
+      <button text-sm btn m="3 t8" @click="router.back()">
+        Back
+      </button>
+    </div>
+  </main>
+</template>