feat: map eBay 'Produktart' aspect to ArticleType name

Adds articleTypeName as a mappable article field — Article.getArticleTypeName()
proxies to articleType.getName(). 'Produktart' auto-detects via alias, so the
import UI pre-selects this mapping and the eBay listing gets the type name as
the Produktart aspect value automatically.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

src/Domain/Article/Article.php

@@ -135,6 +135,11 @@ class Article
         return $this->articleType;
     }
 
+    public function getArticleTypeName(): string
+    {
+        return $this->articleType->getName();
+    }
+
     public function getSku(): string
     {
         return $this->sku;

src/Infrastructure/Http/Controller/Admin/EbayAspectImportController.php

@@ -52,14 +52,16 @@ final class EbayAspectImportController extends AbstractController
      * key = Article getter suffix / property name, value = German UI label.
      */
     private const ARTICLE_FIELDS = [
-        'manufacturer' => 'Hersteller (Marke)',
-        'modelNumber'  => 'Herstellernummer (PN / MPN)',
-        'modelName'    => 'Modellname',
-        'serialNumber' => 'Seriennummer',
+        'articleTypeName' => 'Produktart (Artikel-Typ)',
+        'manufacturer'    => 'Hersteller (Marke)',
+        'modelNumber'     => 'Herstellernummer (PN / MPN)',
+        'modelName'       => 'Modellname',
+        'serialNumber'    => 'Seriennummer',
     ];
 
     /** eBay aspect names (lowercase) that auto-match to article fields. */
     private const ARTICLE_FIELD_ALIASES = [
+        'produktart'         => 'articleTypeName',
         'marke'              => 'manufacturer',
         'brand'              => 'manufacturer',
         'hersteller'         => 'manufacturer',