feat: Divi save pipeline – tree_rev lock, kses-safe save, revision, flags, cache, ToolResult

DiviSaver/DiviWriter/DiviComposition/DiviChange, WpValueSanitizer (S4),
WpMediaResolver, DiviFlags (S11), DynamicContentMap from Divi's live
registry (S22), S31 wiring, S35 control strip at apply() entry.

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

src/Integrations/Divi/Pages/DiviFlags.php

@@ -0,0 +1,33 @@
+<?php
+
+declare(strict_types=1);
+
+namespace LIT\MCP\Integrations\Divi\Pages;
+
+use RuntimeException;
+
+/**
+ * Marks an entry as a Divi 5 builder layout, like the Visual Builder's own save does
+ * (Divi 5.2.1 SyncToServerController.php:382-384: _et_pb_use_divi_5 = "on", legacy
+ * _et_pb_use_builder = "on"). Ruling S11: update_post_meta() returns false for an unchanged value too, so success is
+ * checked by reading the flags back. Used by DiviSaver (inside FollowUp) and the Divi content
+ * creation.
+ */
+final class DiviFlags
+{
+    public const FLAGS = ['_et_pb_use_divi_5' => 'on', '_et_pb_use_builder' => 'on'];
+
+    /** @throws RuntimeException When a flag does not read back as set. */
+    public static function set(int $postId): void
+    {
+        foreach (self::FLAGS as $key => $value) {
+            update_post_meta($postId, $key, $value);
+        }
+
+        foreach (self::FLAGS as $key => $value) {
+            if (get_post_meta($postId, $key, true) !== $value) {
+                throw new RuntimeException(sprintf('Divi flag %s of post %d is not "%s".', $key, $postId, $value));
+            }
+        }
+    }
+}