fix: 修复首页空白、小红书/游记封面图、定制页二维码

1. 首页大面积空白：useScrollReveal 添加 MutationObserver，
   确保异步子组件的 .reveal 元素也能触发入场动画

2. 小红书/游记封面图不显示：
   - 小红书 CDN 签名链接过期+防盗链，全部下载到本地
   - 新增 download-covers.mjs 脚本批量下载封面
   - 新增 useImageProxy composable 转换外部 URL
   - 页面 img 标签添加 referrerpolicy="no-referrer"
   - 管理端保存时自动下载外部封面图到本地
   - 种子数据更新为本地路径

3. 定制页微信号文字替换为二维码图片

4. prerender 路由添加 /xiaohongshu 和 /youji

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

scripts/download-covers.mjs

@@ -0,0 +1,132 @@
+/**
+ * 下载小红书/游记封面图片到本地
+ *
+ * 小红书 CDN 签名 URL 会过期且有防盗链，
+ * 此脚本将封面图下载到 public/uploads/covers/ 并更新数据库。
+ *
+ * 运行: node scripts/download-covers.mjs
+ */
+
+import Database from 'better-sqlite3'
+import { writeFileSync, mkdirSync, existsSync } from 'fs'
+import { join, dirname } from 'path'
+import { fileURLToPath } from 'url'
+
+const __dirname = dirname(fileURLToPath(import.meta.url))
+const ROOT = join(__dirname, '..')
+const DB_PATH = join(ROOT, 'server/database/hulai.db')
+const COVERS_DIR = join(ROOT, 'public/uploads/covers')
+
+// 确保目录存在
+mkdirSync(COVERS_DIR, { recursive: true })
+
+/**
+ * 将签名 CDN URL 转为永久可下载的 URL
+ */
+function toPermanentUrl(url) {
+  try {
+    const parsed = new URL(url)
+    if (parsed.hostname === 'sns-webpic-qc.xhscdn.com') {
+      const parts = parsed.pathname.split('/')
+      if (parts.length >= 4) {
+        const imagePath = parts.slice(3).join('/')
+        return `https://ci.xiaohongshu.com/${imagePath}`
+      }
+    }
+    // 已经是永久链接
+    if (parsed.hostname === 'ci.xiaohongshu.com') {
+      return url
+    }
+  } catch {}
+  return url
+}
+
+/**
+ * 下载图片到本地
+ */
+async function downloadImage(url, filename) {
+  const localPath = join(COVERS_DIR, filename)
+  if (existsSync(localPath)) {
+    console.log(`  ⏭ 已存在: ${filename}`)
+    return `/uploads/covers/${filename}`
+  }
+
+  const downloadUrl = toPermanentUrl(url)
+  try {
+    const res = await fetch(downloadUrl, {
+      headers: {
+        'User-Agent': 'Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36',
+      },
+    })
+    if (!res.ok) {
+      console.log(`  ✗ 下载失败 (${res.status}): ${filename} <- ${downloadUrl}`)
+      return null
+    }
+    const buffer = Buffer.from(await res.arrayBuffer())
+    writeFileSync(localPath, buffer)
+    console.log(`  ✓ 已下载: ${filename} (${(buffer.length / 1024).toFixed(1)}KB)`)
+    return `/uploads/covers/${filename}`
+  } catch (err) {
+    console.log(`  ✗ 下载出错: ${filename} - ${err.message}`)
+    return null
+  }
+}
+
+/**
+ * 从 URL 中提取文件扩展名
+ */
+function getExtFromUrl(url) {
+  if (url.includes('webp')) return '.webp'
+  if (url.includes('.jpg') || url.includes('.jpeg')) return '.jpg'
+  if (url.includes('.png')) return '.png'
+  return '.webp' // 小红书默认 webp
+}
+
+async function main() {
+  const db = new Database(DB_PATH)
+
+  for (const key of ['xiaohongshu-wall', 'youji']) {
+    console.log(`\n📦 处理: ${key}`)
+
+    const row = db.prepare('SELECT data FROM site_content WHERE key = ?').get(key)
+    if (!row) {
+      console.log(`  ⚠ 未找到数据: ${key}`)
+      continue
+    }
+
+    const data = JSON.parse(row.data)
+    const notes = data.notes || []
+    let updated = 0
+
+    for (const note of notes) {
+      if (!note.cover) continue
+      // 跳过已经是本地路径的
+      if (note.cover.startsWith('/')) {
+        console.log(`  ⏭ 已是本地: ${note.id}`)
+        continue
+      }
+
+      const ext = getExtFromUrl(note.cover)
+      const filename = `${key.replace('xiaohongshu-wall', 'xhs')}-${note.id}${ext}`
+      const localUrl = await downloadImage(note.cover, filename)
+
+      if (localUrl) {
+        note.cover = localUrl
+        updated++
+      }
+    }
+
+    if (updated > 0) {
+      db.prepare('UPDATE site_content SET data = ? WHERE key = ?')
+        .run(JSON.stringify(data), key)
+      console.log(`\n  ✅ 已更新 ${updated} 张封面到本地路径`)
+    } else {
+      console.log(`\n  ℹ 无需更新`)
+    }
+  }
+
+  db.close()
+  console.log('\n🎉 完成！')
+}
+
+main().catch(console.error)