feat: lit/content-create with Divi short form

New input divi (1-30 sections, short form like lit-divi-insert) builds a Divi 5
layout in one divi/placeholder. The whole description is checked before the
insert (Divi's map for "no entry yet"); the draft is inserted with its normal
WordPress fields only, then DiviContentComposer composes again bound to the new
entry and stores it via DiviSaver::saveNew (same kses window as save(), strict
DiviFlags). A refusal or failure deletes the draft. Result adds tree_rev and the
outline.

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>

src/Plugin.php

@@ -66,11 +66,12 @@ final class Plugin
         (new ChangeLogCleanup($changeLog, $limits))->register();
 
         $schema = self::contentSchema();
+        $divi = new DiviIntegration($schema, $changeLog);
         $registry = new IntegrationRegistry(
             new CoreIntegration(self::pluginDir() . '/docs/guides'),
-            new WordPressIntegration($schema, $changeLog),
+            new WordPressIntegration($schema, $changeLog, $divi->contentComposer()),
             new MediaIntegration($schema, $changeLog, $limits),
-            new DiviIntegration($schema, $changeLog)
+            $divi
         );
 
         $policy = ExposurePolicy::fromOption()->withGroups($registry->groupMap(...));