chore: drop unused export of ApiSearchResponse

Now that the search result container imports from domain/types, the
ApiSearchResponse alias is only consumed inside searchHeritages, so
remove the export to keep the surface narrow.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

Author: zigzagdev

client/src/app/features/search/apis/search-api.ts

@@ -20,7 +20,8 @@ export type SearchParams = {
   perPage?: number;
 };
 
-export type ApiSearchResponse = {
+// Used only inside searchHeritages, no need to export
+type ApiSearchResponse = {
   status: "success" | "error";
   data: {
     items: ApiWorldHeritageDto[];