fix(setup): TLS-Prüfungs-Checkbox aus Cluster-Join-GUI entfernt

Sicherheit des Joins kommt vom HMAC-Token, nicht von TLS-Cert-Trust.
Insecure=true wird jetzt immer im Handler gesetzt — GUI-Nutzer müssen
das nicht kennen oder konfigurieren.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

management-ui/src/pages/Setup/index.tsx

@@ -1,5 +1,5 @@
 import { useState } from 'react'
-import { Alert, Button, Card, Checkbox, Form, Input, Space, Typography, message } from 'antd'
+import { Alert, Button, Card, Form, Input, Space, Typography, message } from 'antd'
 import { ArrowLeftOutlined, CheckCircleOutlined, ClusterOutlined, DesktopOutlined } from '@ant-design/icons'
 import { useNavigate } from 'react-router-dom'
 import { useTranslation } from 'react-i18next'
@@ -24,7 +24,6 @@ interface JoinValues {
   acme_email: string
   primary_fqdn: string
   token: string
-  insecure?: boolean
 }
 
 const FQDN_RE = /^([a-zA-Z0-9]([a-zA-Z0-9-]{0,61}[a-zA-Z0-9])?\.)+[a-zA-Z]{2,}$/
@@ -78,7 +77,6 @@ export default function SetupPage({ onComplete: _onComplete }: Props) {
         acme_email: vals.acme_email.trim().toLowerCase(),
         primary_fqdn: vals.primary_fqdn.trim().toLowerCase(),
         token: vals.token.trim(),
-        insecure: vals.insecure ?? false,
       })
       setJoinDone(true)
     } catch (e: unknown) {
@@ -281,10 +279,6 @@ export default function SetupPage({ onComplete: _onComplete }: Props) {
                 />
               </Form.Item>
 
-              <Form.Item name="insecure" valuePropName="checked">
-                <Checkbox>{t('setup.joinInsecure')}</Checkbox>
-              </Form.Item>
-
               <Form.Item style={{ marginBottom: 0 }}>
                 <Button type="primary" htmlType="submit" block loading={loading}>
                   {t('setup.nodeSubmit')}