Widen VerifyTutorial demo card on the verify page

The centered (non-stacked) demo card was capped at max-w-sm, which looked
undersized inside the wide card on the /verify page. Bump it to max-w-md so
it better fills the parent. The onboarding flow uses the stacked/full-width
path and is unaffected.

src/components/organizations/VerifyTutorial.tsx

@@ -200,7 +200,7 @@ function DemoStage({
     <div
       className={cn(
         'relative w-full select-none',
-        fullWidth ? 'mx-0' : 'mx-auto max-w-sm',
+        fullWidth ? 'mx-0' : 'mx-auto max-w-md',
       )}
       aria-hidden="true"
     >