feat: add nav bar button to publish pending config changes

Shows an orange "Publish Config" button to the left of the alert-pie
for admin users when there are staged config changes. Uses localStorage
to persist staged changes across page navigations so the button appears
on any page, not just settings.

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

hbd/server/templates/settings.html

@@ -871,9 +871,13 @@
         if (count > 0) {
           document.getElementById('pending-count').textContent = count;
           banner.style.display = 'flex';
+          localStorage.setItem('hbd_pending_config', JSON.stringify(_staged));
         } else {
           banner.style.display = 'none';
+          localStorage.removeItem('hbd_pending_config');
         }
+        const navBtn = document.getElementById('nav-publish-btn');
+        if (navBtn) navBtn.style.display = count > 0 ? '' : 'none';
       }
 
       function stageFormSection(sectionId, apiSection) {
@@ -1050,6 +1054,7 @@
 
       function discardAll() {
         Object.keys(_staged).forEach(k => delete _staged[k]);
+        localStorage.removeItem('hbd_pending_config');
         updatePendingBanner();
         window.location.reload();
       }