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/modules/user-parts/urls.php

@@ -32,8 +32,8 @@ function aksrt_get_user_center_url(string $tab = ''): string {
             'assets' => 'credits',
             'vip'    => 'vip', // dedicated vip tab when registered; resolver falls back if missing
             'signin' => 'credits',
-            'invite'    => 'revenue',
-            'promotion' => 'revenue',
+            'invite'    => 'promotion',
+            'promotion' => 'promotion',
         ];
         if (isset($aliases[$tab])) {
             $tab = $aliases[$tab];