feat(ST-507): show code badges on cards, lists and dialogs across the app

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

components/sprint/sprint-header.tsx

@@ -116,6 +116,7 @@ export function SprintHeader({ productId: _productId, productName, sprint, isDem
             <div className="space-y-2 max-h-64 overflow-y-auto">
               {sprintStories.map(story => (
                 <div key={story.id} className="flex items-center justify-between gap-3 p-2 bg-surface-container-low rounded-lg">
+                  {story.code && <span className="font-mono text-[11px] text-muted-foreground shrink-0">{story.code}</span>}
                   <span className="text-sm truncate flex-1">{story.title}</span>
                   <div className="flex gap-1 shrink-0">
                     <button