feat(widgets): simplify locations and paid sidebar

Remove deprecated widget locations and widgets, standardize sidebar labels, and render a compact paid-post purchase card in the article sidebar.

src/Widgets/WidgetUserRanking.php

@@ -17,7 +17,7 @@ class WidgetUserRanking extends \WP_Widget {
 	public function __construct() {
 		parent::__construct(
 			'aksrt_user_ranking',
-			__('用户排行榜', 'aksrt'),
+			__('AKSRT 用户排行榜', 'aksrt'),
 			[
 				'description' => __('按积分、文章数或粉丝数排行的用户列表。', 'aksrt'),
 				'classname'   => 'widget_aksrt_user_ranking',