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/profile-promotion.php

@@ -0,0 +1,25 @@
+<?php
+/**
+ * User center promotion panel (invite / 推广中心).
+ *
+ * Standalone dashboard tab that hosts the invite card. Reuses the existing
+ * invite REST contract and credits.js `initInvite()` binding via the
+ * `[data-aksrt-invite]` card in profile-invite.php.
+ *
+ * @package AKSRT
+ */
+
+defined('ABSPATH') || exit;
+
+$context = is_array($args['context'] ?? null) ? $args['context'] : [];
+$user_id = (int) ($context['user_id'] ?? get_current_user_id());
+if ($user_id <= 0) {
+	echo '<div class="uc-panel-empty muted-2-color">' . esc_html__('请先登录', 'aksrt') . '</div>';
+	return;
+}
+
+$currency_name = (string) ($context['currency_name'] ?? __('积分', 'aksrt'));
+?>
+<div class="uc-promotion-page" data-aksrt-promotion-page>
+	<?php require __DIR__ . '/profile-invite.php'; ?>
+</div>