fix(rbac): Viewer-Rolle in Detail-Pages + ActionButtons — Edit ebenfalls sperren

- ActionButtons: Edit-Button wird für Viewer wie Delete gesperrt (Tooltip zeigt Reason)
- Domains/Detail: isViewer-Flag an alle Sub-Panels weitergegeben; Save-, TLS-Cert-,
  Routing-Rules- und Headers-Buttons für Viewer disabled
- Backends/Detail: Save-Button + ServerPanel Add-Button für Viewer disabled
- i18n: domains.backendUp/backendDown Keys (waren noch hardkodiert)

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

management-ui/src/components/ActionButtons.tsx

@@ -9,9 +9,9 @@ import { useAuthStore } from '../stores/auth'
 //
 // Either prop may be omitted to suppress that button — useful for
 // rows that aren't editable (e.g. builtin services).
-// Viewer-role accounts automatically get delete disabled — mutations
-// are blocked at the API level too, but hiding the button avoids
-// confusing "access denied" errors for read-only users.
+// Viewer-role accounts get both buttons disabled — mutations are
+// blocked at the API level too, but disabling here avoids confusing
+// "access denied" errors for read-only users.
 interface ActionButtonsProps {
   onEdit?: () => void
   onDelete?: () => void
@@ -35,20 +35,23 @@ export default function ActionButtons({
   const role = useAuthStore((s) => s.user?.role)
   const isViewer = role === 'viewer'
 
+  const viewerReason = isViewer ? t('auth.viewerBadge') : undefined
+
+  const editDis = editDisabled || isViewer
+  const editDisReason = isViewer ? viewerReason : editDisabledReason
+
   const delDisabled = deleteDisabled || isViewer
-  const delDisabledReason = isViewer
-    ? t('auth.viewerBadge')
-    : deleteDisabledReason
+  const delDisabledReason = isViewer ? viewerReason : deleteDisabledReason
 
   return (
     <Space size={4}>
       {onEdit && (
-        <Tooltip title={editDisabled ? editDisabledReason : (editTooltip ?? t('common.edit'))}>
+        <Tooltip title={editDis ? editDisReason : (editTooltip ?? t('common.edit'))}>
           <Button
             type="text"
             size="small"
             icon={<EditOutlined />}
-            disabled={editDisabled}
+            disabled={editDis}
             onClick={onEdit}
           />
         </Tooltip>