fix(captcha): wire scene switches and rename menu to 人机验证

- Admin: 登录权限 → 人机验证; 停用场景 → 启用场景 (opt-in)
- Normalize enabled_scenarios with legacy disabled_scenarios BC
- Sign-in: never soft-bypass captcha; cancel unlocks button
- Captcha JS: cancel path finishes pending callback as false

inc/classes/admin/schema/class-aksrt-admin-schema-extensions-security.php

@@ -53,7 +53,7 @@ class AKSRT_Admin_Schema_Extensions_Security {
                     ['key' => 'remove_more_wp_head', 'label' => '移除WP head多余代码', 'type' => 'switch', 'default' => true],
                 ]],
                 ['key' => 'captcha-note', 'title' => '人机验证', 'fields' => [
-                    ['key' => 'captcha_redirect_hint', 'label' => '配置入口', 'type' => 'notice', 'alertType' => 'info', 'alertContent' => '人机验证（腾讯云 / 阿里云 / Cloudflare / 极验）请到「功能&权限 → 登录权限」统一配置；本页不再维护验证码字段。'],
+                    ['key' => 'captcha_redirect_hint', 'label' => '配置入口', 'type' => 'notice', 'alertType' => 'info', 'alertContent' => '人机验证（腾讯云 / 阿里云 / Cloudflare / 极验）请到「功能&权限 → 人机验证」统一配置；本页不再维护验证码字段。'],
                 ]],
                 ['key' => 'rate-limit', 'title' => '频率限制', 'fields' => [
                     ['key' => 'brush_limit_post_enabled', 'label' => '文章发布限制', 'type' => 'switch', 'default' => false],