Rewrite captcha core around aksrt_captcha_config only, require captcha on login/comment/SMS/phone auth and related gates, wire frontend token collection, and remove dead dual-source security settings plus slider enqueue.
抽出 sign.css,统一全页登录/注册与找回/绑定视觉;中文文案与用户协议契约对齐 Auth_Service;弹层字段与 logo 同步。 Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>