feat(nav): close P0/P1 parity gaps (nav style, history, plate, admin build)

Wire header_nav_style transparent/blur, login history sync, plate publish
type, clean dead search CSS, rebuild admin SPA locally (build gitignored).

assets/js/header-newadd.js

@@ -45,7 +45,7 @@
     openMenu.classList.remove('is-open');
     openMenu.setAttribute('hidden', '');
     openMenu.setAttribute('aria-hidden', 'true');
-    if (openToggle) openToggle.setAttribute('aria-expanded', 'false');
+    if (openToggle && openToggle.setAttribute) openToggle.setAttribute('aria-expanded', 'false');
     if (openRoot) openRoot.classList.remove('is-open');
     // Return menu to original root so SSR structure stays consistent.
     if (openRoot && openMenu.parentNode !== openRoot) {
@@ -60,6 +60,11 @@
     var toggle = root.querySelector('.newadd-btns__toggle');
     var menu = root.querySelector('.drop-newadd');
     if (!toggle || !menu) return;
+    if (toggle.tagName === 'SPAN' || toggle.tagName === 'DIV') {
+      toggle.setAttribute('role', 'button');
+      toggle.setAttribute('tabindex', '0');
+      if (!toggle.hasAttribute('aria-expanded')) toggle.setAttribute('aria-expanded', 'false');
+    }
 
     if (openRoot && openRoot !== root) closeMenu();
 
@@ -75,7 +80,7 @@
     menu.setAttribute('aria-hidden', 'false');
     menu.classList.add('is-open');
     root.classList.add('is-open');
-    toggle.setAttribute('aria-expanded', 'true');
+    if (toggle.setAttribute) toggle.setAttribute('aria-expanded', 'true');
     placeMenu(toggle, menu);
   }
 
@@ -136,6 +141,11 @@
     var toggle = root.querySelector('.newadd-btns__toggle');
     var menu = root.querySelector('.drop-newadd');
     if (!toggle || !menu) return;
+    if (toggle.tagName === 'SPAN' || toggle.tagName === 'DIV') {
+      toggle.setAttribute('role', 'button');
+      toggle.setAttribute('tabindex', '0');
+      if (!toggle.hasAttribute('aria-expanded')) toggle.setAttribute('aria-expanded', 'false');
+    }
 
     // CSS hover no longer drives this control.
     root.classList.add('is-js-portal');