feat(shell): polish header/hero overlay and footer zibll classes

Make show-slide header overlay the hero, dual-class nav/footer shells
toward zibll selectors, and add a small footer layout bridge for logo,
contact, and float buttons.

header.php

@@ -219,7 +219,7 @@ if (!empty($aksrt_bg_styles)) {
 				wp_nav_menu([
 					'theme_location' => 'primary',
 					'container'      => false,
-					'menu_class'     => 'nav-desktop',
+					'menu_class'     => 'nav-desktop navbar-nav',
 					'fallback_cb'    => false,
 					'depth'          => 3,
 				]);