feat(widgets): marketing card empty states + feature intro media lazy

Admin null shells for feature/highlights/cover/icon/combo/tilt/buttons
and video player; feature intro lazy images + deferred inactive videos.

src/AKSRT/Widgets/WidgetVideoPlayer.php

@@ -36,8 +36,9 @@ class WidgetVideoPlayer extends \WP_Widget {
 		if ($video_url === '') {
 			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__('视频播放器：', 'aksrt') . '</b>' .
-					esc_html__('请配置视频 URL 或移出该模块', 'aksrt') . '</div>';
+				echo function_exists('aksrt_get_widget_null')
+					? aksrt_get_widget_null(__('请配置视频 URL', 'aksrt')) // phpcs:ignore WordPress.Security.EscapeOutput.OutputNotEscaped
+					: '<div class="c-red muted-box mb20"><b>' . esc_html__('视频播放器：', 'aksrt') . '</b>' . esc_html__('请配置视频 URL 或移出该模块', 'aksrt') . '</div>';
 				echo $args['after_widget']; // phpcs:ignore WordPress.Security.EscapeOutput.OutputNotEscaped
 			}
 			return;