refactor(emex): rewrite EMEX integration, add category fallback

Replace browser-based Puppeteer scraper with standalone scraper wrapper.
Add EMEX as fallback source for categories when PL24 is unavailable.
Update vehicle decoding to use new synchronous EMEX API.

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

apps/api/src/database/schema/core.ts

@@ -259,6 +259,7 @@ export const categories = pgTable(
   (table) => [
     index("categories_vehicle_id_idx").on(table.vehicleId),
     index("categories_parent_id_idx").on(table.parentId),
+    uniqueIndex("categories_vehicle_name_source_idx").on(table.vehicleId, table.name, table.source),
   ],
 );
 

apps/api/src/database/seed.ts

@@ -28,6 +28,7 @@ const BRANDS_DATA = [
   { name: "Jaguar", slug: "jaguar" },
   { name: "Mini", slug: "mini" },
   { name: "Dacia", slug: "dacia" },
+  { name: "Subaru", slug: "subaru" },
 ];
 
 const PLANS_DATA = [