Rename module site_structure → structural_pages and vocabulary site_section → site_sections

Renames the module from site_structure to structural_pages and pluralizes
the taxonomy vocabulary machine name from site_section to site_sections,
updating all config, PHP, translations, and documentation references
while preserving field_site_section, clears_site_section, and $site_section_id.

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

modules/structural_pages_group/src/Plugin/ParentEntityHandler/GroupHandler.php

@@ -0,0 +1,51 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Drupal\structural_pages_group\Plugin\ParentEntityHandler;
+
+use Drupal\Core\Entity\EntityInterface;
+use Drupal\Core\Routing\RouteMatchInterface;
+use Drupal\Core\StringTranslation\TranslatableMarkup;
+use Drupal\group\Entity\GroupInterface;
+use Drupal\structural_pages\Attribute\ParentEntityHandler;
+use Drupal\structural_pages\ParentEntityHandler\ParentEntityHandlerBase;
+
+/**
+ * Handler for group entities.
+ *
+ * This handler is provided by the structural_pages_group submodule and is only
+ * available when the Group module is installed.
+ */
+#[ParentEntityHandler(
+  id: 'group',
+  label: new TranslatableMarkup('Groups (group)'),
+  entity_type_id: 'group',
+  provider_module: 'group',
+  clears_site_section: TRUE,
+  sort_field: 'label',
+  weight: 15,
+)]
+class GroupHandler extends ParentEntityHandlerBase {
+
+  /**
+   * {@inheritdoc}
+   */
+  public function getEntityFromRoute(RouteMatchInterface $route_match): ?EntityInterface {
+    $group = $route_match->getParameter('group');
+
+    if (!$group instanceof GroupInterface) {
+      return NULL;
+    }
+
+    return $group;
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function handlesEntity(EntityInterface $entity): bool {
+    return $entity instanceof GroupInterface;
+  }
+
+}