Render streamed assistant responses as Markdown

frontend/src/ai/MessageMarkdown.tsx

@@ -0,0 +1,24 @@
+import { memo } from "react";
+import MarkdownRender from "markstream-react";
+
+/** Render one assistant text part; final also settles interrupted streams. */
+export const MessageMarkdown = memo(function MessageMarkdown({
+  content,
+  final,
+}: {
+  content: string;
+  final: boolean;
+}) {
+  return (
+    <div className="ai-markdown">
+      <MarkdownRender
+        content={content}
+        final={final}
+        fade={false}
+        htmlPolicy="escape"
+        renderCodeBlocksAsPre
+        batchRendering={false}
+      />
+    </div>
+  );
+});