Initial commit: Site Structure module for Drupal

Drupal module that provides hierarchical site structure management
with support for sections, categories, and content items. Includes
path aliases with tokens, breadcrumb integration, and admin interface.

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

config/install/field.field.node.content_page.field_site_section.yml

@@ -0,0 +1,29 @@
+langcode: en
+status: true
+dependencies:
+  config:
+    - field.storage.node.field_site_section
+    - node.type.content_page
+    - taxonomy.vocabulary.site_section
+  module:
+    - taxonomy
+id: node.content_page.field_site_section
+field_name: field_site_section
+entity_type: node
+bundle: content_page
+label: 'Site Section'
+description: 'For root pages, select the section. For child pages, this field is filled automatically.'
+required: false
+translatable: false
+default_value: {  }
+default_value_callback: ''
+settings:
+  handler: 'default:taxonomy_term'
+  handler_settings:
+    target_bundles:
+      site_section: site_section
+    sort:
+      field: name
+      direction: asc
+    auto_create: false
+field_type: entity_reference