perf(markdown): load katex css lazily via local FullMarkdown wrapper

core-ui no longer bundles katex.min.css (it would base64-inline ~1.4MB
of fonts into the render-blocking global css). Wrap FullMarkdown locally
to co-locate the katex stylesheet so it loads only in the routes that
render math.

src/components/full-markdown/index.tsx

@@ -0,0 +1,12 @@
+// Wrapper around core-ui's FullMarkdown that co-locates the KaTeX stylesheet.
+//
+// core-ui deliberately does NOT bundle katex.min.css (importing it there
+// base64-inlines ~1.4MB of fonts into the shared, render-blocking index.css).
+// Importing it here keeps the KaTeX CSS in the route chunk that actually
+// renders math, so it loads lazily and never blocks first paint.
+//
+// Always import FullMarkdown from this module, not from '@gpustack/core-ui/markdown'.
+import { FullMarkdown } from '@gpustack/core-ui/markdown';
+import 'katex/dist/katex.min.css';
+
+export default FullMarkdown;

src/pages/backends/community/backend-detail.tsx

@@ -1,6 +1,6 @@
+import FullMarkdown from '@/components/full-markdown';
 import { BulbOutlined } from '@ant-design/icons';
 import { AutoTooltip } from '@gpustack/core-ui';
-import { FullMarkdown } from '@gpustack/core-ui/markdown';
 import { useIntl } from '@umijs/max';
 import { Button, Tag } from 'antd';
 import _ from 'lodash';

src/pages/playground/components/multiple-chat/message-body.tsx

@@ -1,5 +1,5 @@
+import FullMarkdown from '@/components/full-markdown';
 import { SimpleAudio } from '@gpustack/core-ui';
-import { FullMarkdown } from '@gpustack/core-ui/markdown';
 import { Input } from 'antd';
 import classNames from 'classnames';
 import _ from 'lodash';

src/pages/playground/components/multiple-chat/think-content.tsx

@@ -1,4 +1,4 @@
-import { FullMarkdown } from '@gpustack/core-ui/markdown';
+import FullMarkdown from '@/components/full-markdown';
 import React from 'react';
 import '../../style/think-content.less';