Add Nunjucks button to footer between 11ty and Tailwind

Agent-Logs-Url: https://github.com/NextCommunity/NextCommunity.github.io/sessions/17998eeb-b35f-412e-85dc-ec4382e6ab9b

Co-authored-by: jbampton <418747+jbampton@users.noreply.github.com>

Author: Copilot

src/_includes/footer-details.njk

@@ -14,6 +14,7 @@
 
       <div class="flex items-center justify-center md:justify-start gap-3 mt-4">
         <a href="https://www.11ty.dev/" target="_blank" class="text-[10px] font-bold px-2 py-1 rounded bg-[var(--bg-card)] border border-[var(--border-color)] text-[var(--text-muted)] hover:text-accent transition-all">🎈 11ty</a>
+        <a href="https://mozilla.github.io/nunjucks/" target="_blank" class="text-[10px] font-bold px-2 py-1 rounded bg-[var(--bg-card)] border border-[var(--border-color)] text-[var(--text-muted)] hover:text-accent transition-all">🔧 Nunjucks</a>
         <a href="https://tailwindcss.com/" target="_blank" class="text-[10px] font-bold px-2 py-1 rounded bg-[var(--bg-card)] border border-[var(--border-color)] text-[var(--text-muted)] hover:text-accent transition-all">🌊 Tailwind</a>
       </div>
     </div>