feat(widgets): product list vs mini DOM + admin empty polish

Differentiate product list/mini row sizes; custom HTML and posts-navs
admin empty states via aksrt_get_widget_null.

src/AKSRT/Widgets/WidgetPostsNavs.php

@@ -27,6 +27,13 @@ class WidgetPostsNavs extends \WP_Widget {
 
 	public function widget($args, $instance): void {
 		if (!is_singular(['post', 'page', 'aksrt_forum_topic', 'aksrt_product'])) {
+			if (current_user_can('manage_options')) {
+				echo $args['before_widget']; // phpcs:ignore WordPress.Security.EscapeOutput.OutputNotEscaped
+				echo function_exists('aksrt_get_widget_null')
+					? aksrt_get_widget_null(__('目录树仅在文章/帖子/商品详情页显示', 'aksrt')) // phpcs:ignore WordPress.Security.EscapeOutput.OutputNotEscaped
+					: '<p class="widget-empty">' . esc_html__('目录树仅在详情页显示', 'aksrt') . '</p>';
+				echo $args['after_widget']; // phpcs:ignore WordPress.Security.EscapeOutput.OutputNotEscaped
+			}
 			return;
 		}