fix(web): defer math rendering while streaming

packages/client/ui-primitives/src/markdown/MarkdownText.tsx

@@ -8,8 +8,9 @@ import { CodeBlock } from './CodeBlock.tsx'
 import 'katex/dist/katex.min.css'
 import css from './MarkdownText.module.css'
 
-const remarkPlugins = [remarkGfm, remarkMath]
-const rehypePlugins = [rehypeKatex]
+const streamingRemarkPlugins = [remarkGfm]
+const settledRemarkPlugins = [remarkGfm, remarkMath]
+const settledRehypePlugins = [rehypeKatex]
 
 function sanitizeUrl(url: string): string {
   try {
@@ -92,7 +93,7 @@ const streamingComponents = buildComponents(true)
 /**
  * Render untrusted assistant-authored Markdown as semantic React elements.
  * @param props - Markdown source text preserved by the session projection;
- * `streaming` renders fences plain (highlighting lands on the finalize swap);
+ * `streaming` renders fences and TeX plain (highlighting and KaTeX land on the finalize swap);
  * `codeLabels` forwards localized copy-button labels to fence CodeBlocks —
  * pass a reference-stable object (memoized per locale revision), because the
  * component table memoizes on its identity and a fresh literal per render
@@ -113,8 +114,8 @@ export function MarkdownText({ text, streaming = false, codeLabels }: {
   return (
     <div className={css.markdown}>
       <ReactMarkdown
-        remarkPlugins={remarkPlugins}
-        rehypePlugins={rehypePlugins}
+        remarkPlugins={streaming ? streamingRemarkPlugins : settledRemarkPlugins}
+        rehypePlugins={streaming ? undefined : settledRehypePlugins}
         components={components}
         urlTransform={safeUrl}
       >