feat(user-center): promote invite into standalone 推广中心 tab

Register a dedicated `promotion` dashboard panel gated by the existing
invite switches (credits + invite reward + invite registration), and move
the invite card out of the revenue tab so 收益中心 is pure earnings/withdrawal.

- src/User/Center.php: register promotion panel; revenue no longer depends
  on invite being on
- inc/helpers/user-center-renderers/profile-promotion.php: new panel body
  hosting the existing [data-aksrt-invite] card
- profile-revenue.php: drop the invite section; aksrt-user-center.php: drop
  unused show_invite_section context, add promotion to built-in tabs + view map
- repoint invite/promotion deep-link aliases from revenue to promotion across
  tab-url builder, tab resolver, runtime tabAliases, urls.php, and the
  revenue-JS enqueue gate
- sidebar-nav.php: add 推广中心 service entry; shell.css: entry icon color;
  sidebar-creator.php: reword revenue card
- UserRuntime.php: allow promotion in configurable tabs

inc/helpers/user-center-renderers/sidebar-nav.php

@@ -11,6 +11,7 @@ $level_url = isset($dashboard_tabs['level'])
 	? aksrt_get_user_center_tab_url('level')
 	: '';
 $auth_url = isset($dashboard_tabs['auth']) ? aksrt_get_user_center_tab_url('auth') : '';
+$promotion_url = isset($dashboard_tabs['promotion']) ? aksrt_get_user_center_tab_url('promotion') : '';
 $orders_available = isset($dashboard_tabs['orders']);
 $orders_url = $orders_available ? (string) ($orders_url ?? '') : '';
 
@@ -21,6 +22,13 @@ $services = array_values(array_filter([
 		'tone'  => 'level',
 		'url'   => $level_url,
 	],
+	[
+		'label' => __('推广中心', 'aksrt'),
+		'icon'  => 'bullhorn',
+		'tone'  => 'promotion',
+		'url'   => $promotion_url,
+		'tab'   => 'promotion',
+	],
 	[
 		'label' => __('官方认证', 'aksrt'),
 		'icon'  => 'id-badge',