fix(messages): default message center slug to messages

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

src/Admin/Schema/SchemaUsers.php

@@ -238,7 +238,7 @@ class SchemaUsers {
                     'groups'     => [
 						['key' => 'basic', 'title' => '基础设置', 'fields' => [
 							['key' => 'message_s', 'label' => '站内通知总开关', 'type' => 'switch', 'default' => true],
-							['key' => 'msg_center_rewrite_slug', 'label' => '消息中心 URL 别名', 'type' => 'input', 'default' => 'message'],
+							['key' => 'msg_center_rewrite_slug', 'label' => '消息中心 URL 别名', 'type' => 'input', 'default' => 'messages'],
 							['key' => 'message_icon_show', 'label' => '通知图标位置', 'type' => 'checkbox', 'default' => ['nav_menu'], 'options' => [
 								['label' => '导航菜单', 'value' => 'nav_menu'],
 								['label' => '头像下拉面板', 'value' => 'avatar_dropdown'],