refactor(web): 前端改用 @stash/ui 组件库

- 新增本地依赖 @stash/ui（file:../../stash-ui），引入其 style.css 与设计令牌
- 页面骨架改用 Layout（contained + header/sider），搜索框改为吸顶
- 卡片/菜单/按钮/标签/头像/分页/空态/提示全部换成组件库组件
- 删除本地 iconfont 与 1400 行手写组件样式，App.css 只保留页面级样式
- 数据层、路由、过滤逻辑未改动；33 个 Rust 测试通过

stash-web/src/components/content/ArticleDetailView.tsx

@@ -1,3 +1,4 @@
+import { Button, Card, Paragraph, Space, Text, Title } from '@stash/ui'
 import type { ArticleItem } from '../../data/types'
 import { ArticleBody } from './ArticleBody'
 
@@ -19,34 +20,49 @@ export function ArticleDetailView({ article, categoryTitle, onBack }: ArticleDet
 
   return (
     <div className="detail-view article-view">
-      <div className="detail-nav card-box">
-        <button type="button" className="detail-back" onClick={onBack}>
-          返回
-        </button>
-        <span className="detail-breadcrumb">{categoryTitle} / 文章</span>
-      </div>
+      <Card padding="sm">
+        <Space justify="between" wrap>
+          <Button variant="ghost" size="sm" onClick={onBack}>
+            返回
+          </Button>
+          <Text size="sm" tone="sub">
+            {categoryTitle} / 文章
+          </Text>
+        </Space>
+      </Card>
 
       <header className="article-head">
-        <h2 className="article-heading">
+        <Title level={2}>
           {article.title}
-          <button type="button" className="item-edit" disabled title="编辑功能待接入">
-            [编辑]
-          </button>
-        </h2>
+          <Button variant="ghost" size="sm" disabled className="item-edit">
+            编辑
+          </Button>
+        </Title>
 
-        <div className="article-meta">
+        <Space gap="sm" wrap>
           {meta.map((text, index) => (
-            <span className="article-meta-item" key={text}>
-              {index > 0 && <i className="article-meta-dot" aria-hidden="true" />}
-              {text}
-            </span>
+            <Space gap="sm" key={text}>
+              {index > 0 && (
+                <span className="article-meta-dot" aria-hidden="true">
+                  ·
+                </span>
+              )}
+              <Text size="sm" tone="muted">
+                {text}
+              </Text>
+            </Space>
           ))}
-        </div>
+        </Space>
       </header>
 
-      <article className="article-body card-box">
-        <ArticleBody markdown={article.body} />
-      </article>
+      <Card padding="lg">
+        <div className="article-body">
+          <Paragraph tone="main" className="article-lead">
+            {article.desc}
+          </Paragraph>
+          <ArticleBody markdown={article.body} />
+        </div>
+      </Card>
     </div>
   )
 }