feat: define footer menu in hugo.toml, render dynamically in partial

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

layouts/partials/footer.html

@@ -51,9 +51,10 @@
     <div class="flex justify-between items-center mt-[54px] pt-6 border-t border-warm/10">
       <span class="font-mono text-[11px] text-ink-faint tracking-[0.04em]">© 2026 Bar Pivoine</span>
       <div class="flex items-center gap-4 font-mono text-[11px] text-ink-faint tracking-[0.04em]">
-        <a href="/imprint/" class="hover:text-ink transition-colors duration-[180ms]">Imprint</a>
-        <span class="text-warm/20">|</span>
-        <a href="https://pivoine.art" class="hover:text-ink transition-colors duration-[180ms]">Pivoine</a>
+        {{- range $i, $item := .Site.Menus.footer -}}
+          {{- if $i }}<span class="text-warm/20">|</span>{{ end -}}
+          <a href="{{ $item.URL }}" class="hover:text-ink transition-colors duration-[180ms]">{{ $item.Name }}</a>
+        {{- end -}}
       </div>
     </div>