Visual header, body, and footer composition screen.

* Drag-and-drop section ordering with automatic saving.
* Add existing reusable documents to regions.
* Remove placements without deleting documents.
* Create independent page-specific copies.
* Shared-document usage warnings.
* Document creation, duplication, deletion protection and filtering.
* Draft and published document states.
* Document and placement scheduling.
* Authenticated homepage preview.
* Draft sections displayed in preview with a clear draft marker.
* Content Composer added to the administration sidebar.
* Public rendering now respects:
    * Publication status
    * Future publication dates
    * Expiry dates
    * Placement start and end dates
    * Enabled state
* Original Saasland homepage remains as the fallback when no composition exists.

Modules/Stylist/Tests/Feature/WelcomeThemeViewTest.php

@@ -15,6 +15,7 @@ final class WelcomeThemeViewTest extends TestCase
     {
         $this->get('/')
             ->assertOk()
-            ->assertViewIs('stylist-theme-saasland::home');
+            ->assertViewIs('stylist-theme-saasland::home')
+            ->assertSee('Transform Your Business With Our SaaS Solution');
     }
 }