feat(widgets): product lazy fallback and admin empty states

Lazyload product list fallback thumbs; surface widget_null admin empties
for notice/stats/faq/slider; stats cards gain data-aksrt-animate.

src/AKSRT/Widgets/WidgetSlider.php

@@ -27,8 +27,9 @@ class WidgetSlider extends \WP_Widget {
 		if (!$slides) {
 			if (current_user_can('manage_options')) {
 				echo $args['before_widget']; // phpcs:ignore WordPress.Security.EscapeOutput.OutputNotEscaped
-				echo '<div class="c-red muted-box mb20"><b>' . esc_html__('幻灯片模块：', 'aksrt') . '</b>' .
-					esc_html__('当前配置下没有可显示的内容，请正确配置或移出该模块', 'aksrt') . '</div>';
+				echo function_exists('aksrt_get_widget_null')
+					? aksrt_get_widget_null(__('当前配置下没有可显示的内容', 'aksrt')) // phpcs:ignore WordPress.Security.EscapeOutput.OutputNotEscaped
+					: '<div class="c-red muted-box mb20"><b>' . esc_html__('幻灯片模块：', 'aksrt') . '</b>' . esc_html__('当前配置下没有可显示的内容，请正确配置或移出该模块', 'aksrt') . '</div>';
 				echo $args['after_widget']; // phpcs:ignore WordPress.Security.EscapeOutput.OutputNotEscaped
 			}
 			return;