Rework app-shell layout

assets/page/header-actions.js

@@ -0,0 +1,16 @@
+// Wires the header-right [ACTIONS] dropdown. The buttons inside keep calling
+// the existing page/actions.js handlers (newPage / movePage / deletePage) and
+// the ?edit link, so the N/E/M keyboard shortcuts continue to work whether or
+// not the menu is open. Toggling reuses the generic wireDropdown mechanism
+// (global-shortcuts.js), which also handles outside-click / Escape close.
+(function () {
+    var trigger = document.querySelector('[data-action="page-actions"]');
+    if (!trigger || typeof wireDropdown !== 'function') return;
+    wireDropdown(trigger);
+    var menu = trigger.parentElement.querySelector('.dropdown-menu');
+    if (!menu) return;
+    // Keep aria-expanded in sync with the menu's open state.
+    trigger.addEventListener('click', function () {
+        trigger.setAttribute('aria-expanded', menu.classList.contains('is-open') ? 'true' : 'false');
+    });
+})();