chore: remove localStorage-based persistence

src/components/RestoreDraftDialog.vue

@@ -1,24 +0,0 @@
-<script setup lang="ts">
-defineProps<{
-  updatedAt: string
-}>()
-
-defineEmits<{
-  restore: []
-  discard: []
-}>()
-</script>
-
-<template>
-  <div class="dialog-overlay" role="dialog" aria-modal="true" aria-labelledby="restore-draft-title">
-    <div class="dialog">
-      <h2 id="restore-draft-title">发现未保存的草稿</h2>
-      <p>检测到本地保存的教案，最近更新时间：{{ updatedAt }}</p>
-      <p>是否恢复上次编辑的内容？</p>
-      <div class="dialog-actions">
-        <button type="button" @click="$emit('restore')">恢复</button>
-        <button type="button" @click="$emit('discard')">放弃</button>
-      </div>
-    </div>
-  </div>
-</template>