feat(api): add VW commercial vehicle support, fix BOM leaf category handling

Add WV1/WV2/WV3 WMI codes for Volkswagen commercial vehicles (Ticari)
mapped to vn_parts service. Skip BOM links in category traversal since
they are leaf categories returning parts, not subgroups.

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

apps/api/src/categories/categories.service.ts

@@ -107,6 +107,11 @@ export class CategoriesService {
       return [];
     }
 
+    // BOM links are leaf categories — they return parts, not subgroups
+    if (linkPath.includes("/bom/")) {
+      return [];
+    }
+
     const subGroups = await this.pl24Service.fetchSubGroupsByPath(
       linkPath,
       catalogInfo.serviceName,

apps/api/src/integrations/corgi/corgi.service.spec.ts

@@ -109,5 +109,13 @@ describe("CorgiService", () => {
       expect(result!.wmi).toBe("3VW");
       expect(result!.isKnown).toBe(true);
     });
+
+    it("should decode a VW Commercial VIN correctly", () => {
+      const result = service.decodeVin("WV2ZZZ2KZ5X071795");
+      expect(result).not.toBeNull();
+      expect(result!.brandName).toBe("Volkswagen");
+      expect(result!.wmi).toBe("WV2");
+      expect(result!.isKnown).toBe(true);
+    });
   });
 });

apps/api/src/integrations/corgi/corgi.service.ts

@@ -16,6 +16,7 @@ const WMI_DATABASE: Record<string, string> = {
   WAU: "Audi", WUA: "Audi",
   // Volkswagen
   WVW: "Volkswagen", WVG: "Volkswagen", "3VW": "Volkswagen",
+  WV1: "Volkswagen", WV2: "Volkswagen", WV3: "Volkswagen",
   // Toyota
   JTD: "Toyota", JTE: "Toyota", JTN: "Toyota", "2T1": "Toyota", "4T1": "Toyota",
   // Fiat

apps/api/src/integrations/pl24/pl24.types.ts

@@ -322,6 +322,11 @@ export const PL24_WMI_SERVICE_MAP: Record<string, string> = {
   "3VW": "vw_parts",
   "9BW": "vw_parts",
 
+  // Volkswagen Ticari (Commercial Vehicles / Nutzfahrzeuge)
+  WV1: "vn_parts",
+  WV2: "vn_parts",
+  WV3: "vn_parts",
+
   // Audi
   WAU: "audi_parts",
   TRU: "audi_parts",