fix: remove unnecessary right padding on runs page

Use negative right margin to counteract the Layout container padding,
giving the runs detail panel more horizontal space especially on
smaller screens.

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

ui/src/pages/AgentDetail.tsx

@@ -1313,7 +1313,7 @@ function RunsTab({
 
   // Desktop: side-by-side layout
   return (
-    <div className="flex gap-0">
+    <div className="flex gap-0 -mr-4 md:-mr-6">
       {/* Left: run list — border stretches full height, content sticks */}
       <div className={cn(
         "shrink-0 border border-border rounded-lg",