统一 React 管理后台，修复评论换行与帖子置顶

- /admin/* 全部由 React SPA 渲染，替代旧版 HTML 后台页面
- 新增仪表盘、帖子/评论/用户管理、系统设置与 JSON API
- 帖子详情页支持管理员置顶；评论换行显示修复

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

embed_static/static/spa/assets/input-BN5iO3BQ.js

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+import{r as t,j as i}from"./react-vendor-CFzzFOsg.js";import{c as n}from"./index-DurEdRMk.js";const a=t.forwardRef(({className:e,type:o,...r},s)=>i.jsx("input",{type:o,className:n("flex h-9 w-full rounded-md border border-input bg-background px-3 py-1 text-sm shadow-sm transition-colors file:border-0 file:bg-transparent file:text-sm file:font-medium placeholder:text-muted-foreground focus-visible:outline-none focus-visible:ring-1 focus-visible:ring-ring disabled:cursor-not-allowed disabled:opacity-50",e),ref:s,...r}));a.displayName="Input";export{a as I};