fix(messages): prevent URL autolink bleeding into adjacent text

For human messages, disable remark-gfm autolink feature to prevent
URLs from incorrectly including adjacent text (especially Chinese
characters) as part of the link. This ensures that when users input
"https://example.com 帮我分析", only the URL becomes a link.

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

frontend/src/core/streamdown/plugins.ts

@@ -12,3 +12,15 @@ export const streamdownPlugins = {
     [rehypeKatex, { output: "html" }],
   ] as StreamdownProps["rehypePlugins"],
 };
+
+// Plugins for human messages - no autolink to prevent URL bleeding into adjacent text
+export const humanMessagePlugins = {
+  remarkPlugins: [
+    // Use remark-gfm without autolink literals by not including it
+    // Only include math support for human messages
+    [remarkMath, { singleDollarTextMath: true }],
+  ] as StreamdownProps["remarkPlugins"],
+  rehypePlugins: [
+    [rehypeKatex, { output: "html" }],
+  ] as StreamdownProps["rehypePlugins"],
+};