fix: tb-create-template rolls back posts Divi inserted before failing (ruling Q19)

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

src/Integrations/Divi/ThemeBuilder/InsertedBeforeFailure.php

@@ -0,0 +1,24 @@
+<?php
+
+declare(strict_types=1);
+
+namespace LIT\MCP\Integrations\Divi\ThemeBuilder;
+
+use RuntimeException;
+use Throwable;
+
+defined('ABSPATH') || exit;
+
+/**
+ * Divi failed after its own wp_insert_post() already created posts (a throwing hook, a wp_die() turned into an
+ * exception by DiviThemeBuilder::guarded()): $postIds are the new posts of the expected types, so the caller can
+ * roll them back (ruling Q19). The message is the original failure's.
+ */
+final class InsertedBeforeFailure extends RuntimeException
+{
+    /** @param list<int> $postIds */
+    public function __construct(string $message, public readonly array $postIds, ?Throwable $previous = null)
+    {
+        parent::__construct($message, 0, $previous);
+    }
+}