Adiciona sub-módulo site_users_user_content

Registra o handler de entidade User para o módulo Structural Pages,
permitindo que nós content_page usem um usuário como entidade pai e
viabilizando a hierarquia de páginas do microsite (/user/{id}/...).

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

modules/site_users_user_content/site_users_user_content.info.yml

@@ -0,0 +1,8 @@
+name: 'Site Users User Content'
+type: module
+description: 'Provides User entity support as parent type for Structural Pages module.'
+package: 'Site Users'
+core_version_requirement: ^10.3 || ^11
+dependencies:
+  - structural_pages:structural_pages
+  - site_users:site_users

modules/site_users_user_content/src/Plugin/ParentEntityHandler/UserHandler.php

@@ -0,0 +1,25 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Drupal\site_users_user_content\Plugin\ParentEntityHandler;
+
+use Drupal\Core\StringTranslation\TranslatableMarkup;
+use Drupal\structural_pages\Attribute\ParentEntityHandler;
+use Drupal\structural_pages\ParentEntityHandler\ParentEntityHandlerBase;
+
+/**
+ * Handler for user entities.
+ *
+ * Allows content_page nodes to use a user entity as their parent, enabling
+ * personal microsite content organisation without a site section.
+ */
+#[ParentEntityHandler(
+  id: 'user',
+  label: new TranslatableMarkup('Users (user)'),
+  entity_type_id: 'user',
+  clears_site_section: TRUE,
+  sort_field: 'name',
+  weight: 30,
+)]
+class UserHandler extends ParentEntityHandlerBase {}