feat(templates): add archive-header and post-grid components

- Add ArchiveHeader component (schema, renderer, formbuilder)
- Add PostGrid component (schema, renderer, formbuilder)
- Unify archive templates (home, archive, category, tag,
  author, date, search)
- Add page visibility system with VisibilityDefaults
- Register components in AdminDashboardRenderer
- Fix boolean conversion in functions-addon.php
- All 172 unit tests passed

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

Admin/Infrastructure/Ui/ComponentGroupRegistry.php

@@ -37,7 +37,7 @@ final class ComponentGroupRegistry
                 'label' => __('Contenido Principal', 'roi-theme'),
                 'icon' => 'bi-file-richtext',
                 'description' => __('Secciones principales de páginas y posts', 'roi-theme'),
-                'components' => ['hero', 'featured-image', 'table-of-contents', 'related-post']
+                'components' => ['hero', 'featured-image', 'table-of-contents', 'related-post', 'archive-header', 'post-grid']
             ],
             'ctas-conversion' => [
                 'label' => __('CTAs & Conversión', 'roi-theme'),