fix: refuse private/unpublished menu links, write only changed menu items

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01At3V6SjwbMe6eMzVGW3Hs7

src/Integrations/WordPress/Menus/MenuOperations.php

@@ -66,16 +66,18 @@ final class MenuOperations
             return 'Objekt erwartet.';
         }
 
+        $op = $operation['op'] ?? '';
         $parentId = (int) ($operation['parent_id'] ?? 0);
         $parentKey = $parentId > 0 ? 'id:' . $parentId : self::ROOT;
-        if (! isset($children[$parentKey])) {
+        // parent_id only matters where something is placed; remove ignores it.
+        if (in_array($op, ['add', 'move'], true) && ! isset($children[$parentKey])) {
             return 'parent_id ist kein Eintrag dieses Menüs.';
         }
 
         $position = isset($operation['position']) ? (int) $operation['position'] : null;
         $key = 'id:' . (int) ($operation['id'] ?? 0);
 
-        switch ($operation['op'] ?? '') {
+        switch ($op) {
             case 'add':
                 if (! is_array($operation['item'] ?? null)) {
                     return 'item fehlt.';