fix(code-block): enable horizontal scrolling for long lines in code blocks (#439)

* fix(code-block): enable horizontal scrolling for long lines in code blocks

Change overflow-hidden to overflow-x-auto on the code block body container
so that long single-line comments and other long code lines are scrollable
horizontally instead of being silently clipped.

Fixes #438

* Add changeset for code block horizontal scroll fix

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

---------

Co-authored-by: Dmitrii Troitskii <jsleitor@gmail.com>
Co-authored-by: Hayden Bleasel <hello@haydenbleasel.com>
Co-authored-by: Claude Opus 4.6 <noreply@anthropic.com>

Author: 4 people

.changeset/fix-code-block-horizontal-scroll.md

@@ -0,0 +1,5 @@
+---
+"streamdown": patch
+---
+
+Enable horizontal scrolling on code blocks so long lines are accessible instead of being clipped by `overflow-hidden`.

packages/streamdown/lib/code-block/body.tsx

@@ -82,7 +82,7 @@ export const CodeBlockBody = memo(
       <div
         className={cn(
           className,
-          "overflow-hidden rounded-md border border-border bg-background p-4 text-sm"
+          "overflow-x-auto rounded-md border border-border bg-background p-4 text-sm"
         )}
         data-language={language}
         data-streamdown="code-block-body"