fix(home): allow welcome CTA to wrap on narrow viewports

The Button base sets whitespace-nowrap + fixed h-12, so the French
welcome CTA "En savoir plus sur le Centre pour l'art et l'écologie"
overflowed the mobile viewport. Override on this instance:
whitespace-normal, h-auto + py-3, max-w-full, text-balance, and a
larger rounded-3xl to keep the pill shape on two lines.

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

src/views/HomeView.vue

@@ -96,7 +96,11 @@ const featuredEvents = [
           <p class="mt-6 text-base leading-relaxed text-foreground/90 md:text-lg">
             {{ t('home.welcome.body') }}
           </p>
-          <Button as-child variant="outline" class="mt-8">
+          <Button
+            as-child
+            variant="outline"
+            class="mt-8 h-auto max-w-full whitespace-normal rounded-3xl py-3 text-balance"
+          >
             <RouterLink to="/concept">{{ t('home.welcome.cta') }}</RouterLink>
           </Button>
         </div>