fix(captcha): 1:1 align bind-phone and real status contracts

Add bind_phone captcha scene across schema/runtime/UI, require captcha on
phone bind, return real captcha status objects instead of legacy option
aliases, and harden form discovery for page-sign auth forms.

assets/admin/src/pages/extensions/ExtensionTools.vue

@@ -136,8 +136,8 @@ onMounted(async () => {
       services.value[0].status = svc.sms?.provider || (s.sms_enabled ? '已启用' : '未配置')
       services.value[1].available = !!(svc.wechat?.available ?? s.wechat_enabled)
       services.value[1].status = svc.wechat?.provider || (s.wechat_enabled ? '已启用' : '未配置')
-      services.value[2].available = !!(svc.captcha?.available ?? s.captcha_enabled)
-      services.value[2].status = svc.captcha?.provider || (s.captcha_enabled ? '已启用' : '未配置')
+      services.value[2].available = !!(svc.captcha?.available ?? svc.captcha?.configured)
+      services.value[2].status = svc.captcha?.provider || (svc.captcha?.enabled ? '已启用' : '未配置')
       services.value[3].available = !!(svc.push?.available ?? s.baidu_push_enabled)
       services.value[3].status = svc.push?.provider || (s.baidu_push_enabled ? '已启用' : '未配置')
       services.value[4].available = !!(svc.audit?.available ?? s.content_audit_enabled)