perf(vuepress): 延迟加载 LayoutToggle 和 UnlockContent 组件

- LayoutToggle 替换为 DeferredLayoutToggle 延迟挂载
- UnlockContent 改为 defineAsyncComponent 异步加载
- 关闭 print 和 photoSwipe 减少打包体积
- agent-memory.md 修复"长期记忆和 RAG"标题层级跳级

Co-authored-by: Cursor <cursoragent@cursor.com>