feat: {{link:ID}} placeholder via Divi's post_link_url dynamic content

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

src/Integrations/Divi/Pages/DiviComposition.php

@@ -6,6 +6,7 @@ namespace LIT\MCP\Integrations\Divi\Pages;
 
 use LIT\MCP\Integrations\Divi\Compose\AttrWriter;
 use LIT\MCP\Integrations\Divi\Compose\Composer;
+use LIT\MCP\Integrations\Divi\Compose\LinkTargets;
 use LIT\MCP\Integrations\Divi\Compose\MediaResolver;
 use LIT\MCP\Integrations\Divi\Compose\Placeholders;
 use LIT\MCP\Integrations\Divi\Compose\ShortformWriter;
@@ -45,7 +46,8 @@ class DiviComposition
         private DesignSystemReader $design,
         private ValueSanitizer $sanitizer = new WpValueSanitizer(),
         private MediaResolver $media = new WpMediaResolver(),
-        private DynamicContentMap $dynamicContent = new DynamicContentMap()
+        private DynamicContentMap $dynamicContent = new DynamicContentMap(),
+        private LinkTargets $links = new WpLinkTargets()
     ) {
     }
 
@@ -83,7 +85,7 @@ class DiviComposition
      */
     public function placeholders(): Placeholders
     {
-        return $this->placeholders ??= new Placeholders($this->design->read());
+        return $this->placeholders ??= new Placeholders($this->design->read(), $this->links);
     }
 
     /** The one choke point of this composition (ValueCleaner, rulings S1–S3, S7, S13, S28, S32). */

src/Integrations/Divi/Pages/WpLinkTargets.php

@@ -0,0 +1,30 @@
+<?php
+
+declare(strict_types=1);
+
+namespace LIT\MCP\Integrations\Divi\Pages;
+
+use LIT\MCP\Integrations\Divi\Compose\LinkTargets;
+use WP_Post;
+
+defined('ABSPATH') || exit;
+
+/**
+ * {{link:<ID>}} targets from WordPress: the entry exists, lives (no trash, auto-draft or
+ * revision) and the current user may read it (read_post, like select_post settings, S37).
+ * Missing and unreadable entries give the same null (no existence oracle).
+ */
+final class WpLinkTargets implements LinkTargets
+{
+    private const DEAD = ['trash', 'auto-draft', 'inherit'];
+
+    public function postTypeOf(int $id): ?string
+    {
+        $post = get_post($id);
+        if (! $post instanceof WP_Post || in_array((string) $post->post_status, self::DEAD, true)) {
+            return null;
+        }
+
+        return current_user_can('read_post', $id) ? (string) $post->post_type : null;
+    }
+}