POL-125: Fix profile label — restore "Instagram" text

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

web/src/app/(app)/profile/page.tsx

@@ -77,7 +77,7 @@ export default function ProfilePage() {
           <div className="flex items-center justify-between py-2">
             <span className="flex items-center gap-2 text-sm text-dim">
               <AtSign size={14} />
-              AtSign
+              Instagram
             </span>
             <span className="text-sm text-foreground">{user.instagram_handle}</span>
           </div>