feat: write results warn about sections built like a library section (spec §5.5)

SimilarSections compares inserted sections (not global instances) with
at most 200 editable library section entries by structure fingerprint,
read lazily once per request, only while library IDs may be named (P13).
lit/library-insert is not asked.

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

tests/Support/DiviWriterFixture.php

@@ -6,6 +6,7 @@ namespace LIT\MCP\Tests\Support;
 
 use LIT\MCP\Integrations\Divi\Design\DesignSystemReader;
 use LIT\MCP\Integrations\Divi\Library\GlobalEdits;
+use LIT\MCP\Integrations\Divi\Library\SimilarSections;
 use LIT\MCP\Integrations\Divi\Pages\DiviComposition;
 use LIT\MCP\Integrations\Divi\Pages\DiviPageLoader;
 use LIT\MCP\Integrations\Divi\Pages\DiviSaver;
@@ -102,7 +103,8 @@ final class DiviWriterFixture
         bool $unfiltered = false,
         ?DiviPageLoader $loader = null,
         ?GlobalEdits $globals = null,
-        ?ThemeBuilderEdits $themeBuilder = null
+        ?ThemeBuilderEdits $themeBuilder = null,
+        ?SimilarSections $similar = null
     ): DiviWriter {
         $design = self::designReader();
 
@@ -113,7 +115,8 @@ final class DiviWriterFixture
             $design,
             self::composition($design, $unfiltered),
             $globals,
-            $themeBuilder
+            $themeBuilder,
+            $similar
         );
     }
 }