Update documentation with Site Structure Menu block

Add section describing the dynamic menu block features,
configuration options, and usage instructions. Update file
structure and changelog.

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

docs/DESIGN.md

@@ -186,6 +186,45 @@ Configuration form at `/admin/config/local-modules/site-structure` that allows a
 - Select which taxonomy vocabularies can be used as parents
 - Changes automatically update the field configuration
 
+### 10. Block: Site Structure Menu
+
+Dynamic menu block that renders hierarchical navigation based on the content structure.
+
+**Features**:
+- Automatically detects the ancestor entity (taxonomy term, user, or group)
+- Renders all content_page hierarchies under the ancestor
+- Supports configurable depth limit
+- Highlights active trail (current page and its ancestors)
+- Proper cache invalidation by node and route
+
+**Configuration options**:
+
+| Option | Default | Description |
+|--------|---------|-------------|
+| Maximum depth | 3 | Number of levels to display (1-10) |
+| Show ancestor title | Yes | Display ancestor entity title as header |
+| Expand active trail | Yes | Highlight the path to current page |
+
+**Menu structure example**:
+
+```
+Documentation (ancestor: taxonomy term)
+├── Getting Started          ← level 1 (content_page → term)
+│   ├── Installation         ← level 2 (content_page → node)
+│   └── Configuration        ← level 2
+├── User Guide               ← level 1 (content_page → term)
+│   ├── Basic Usage          ← level 2
+│   └── Advanced Topics      ← level 2
+│       └── API Integration  ← level 3 (content_page → node)
+└── FAQ                      ← level 1 (content_page → term)
+```
+
+**Usage**:
+1. Navigate to Structure > Block layout
+2. Place "Site Structure Menu" block in desired region
+3. Configure visibility (e.g., show only on content_page nodes)
+4. Adjust depth and display options as needed
+
 ---
 
 ## File Structure
@@ -193,11 +232,12 @@ Configuration form at `/admin/config/local-modules/site-structure` that allows a
 ```
 site_structure/
 ├── site_structure.info.yml              # Metadata and dependencies
-├── site_structure.module                # Hooks (presave, tokens)
+├── site_structure.module                # Hooks (presave, tokens, theme)
 ├── site_structure.install               # Installation hooks
 ├── site_structure.services.yml          # Service registration
 ├── site_structure.routing.yml           # Route definitions
 ├── site_structure.links.menu.yml        # Admin menu links
+├── site_structure.libraries.yml         # Asset libraries (CSS)
 │
 ├── config/
 │   ├── install/
@@ -226,6 +266,12 @@ site_structure/
 │   └── schema/
 │       └── site_structure.schema.yml    # Config schema
 │
+├── css/
+│   └── site-structure-menu.css          # Menu block styles
+│
+├── templates/
+│   └── site-structure-menu.html.twig    # Menu block template
+│
 ├── translations/
 │   └── pt-br.po                         # Portuguese (Brazil) translation
 │
@@ -233,8 +279,12 @@ site_structure/
 │   ├── Breadcrumb/
 │   │   └── SectionBreadcrumbBuilder.php
 │   │
-│   └── Form/
-│       └── SiteStructureSettingsForm.php
+│   ├── Form/
+│   │   └── SiteStructureSettingsForm.php
+│   │
+│   └── Plugin/
+│       └── Block/
+│           └── SiteStructureMenuBlock.php  # Dynamic menu block
 │
 └── docs/
     └── DESIGN.md                        # This document
@@ -343,3 +393,4 @@ The module supports the Group module for content organization:
 | 1.0.0 | - | Initial version |
 | 1.1.0 | - | Added dynamic_entity_reference support for multi-type parents |
 | 1.2.0 | - | Added user and group entity support as parent types |
+| 1.3.0 | - | Added Site Structure Menu block for dynamic hierarchical navigation |