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

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

tests/Support/ComposeFixture.php

@@ -6,6 +6,7 @@ namespace LIT\MCP\Tests\Support;
 
 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;
@@ -128,9 +129,24 @@ final class ComposeFixture
         };
     }
 
+    /** Link targets of the tests: 839 is a page, 840 a post; everything else is missing, trashed or unreadable. */
+    public static function links(): LinkTargets
+    {
+        return new class implements LinkTargets {
+            public function postTypeOf(int $id): ?string
+            {
+                return match ($id) {
+                    839 => 'page',
+                    840 => 'post',
+                    default => null,
+                };
+            }
+        };
+    }
+
     public static function placeholders(): Placeholders
     {
-        return new Placeholders(DiviFixtures::designSystem());
+        return new Placeholders(DiviFixtures::designSystem(), self::links());
     }
 
     /** The strict $variable(…)$ checker for the sample design system and the default map. */