Fix seat class name assignment to ensure consistency with fare engine resolution

apps/edr-passenger-api/src/modules/search/search.service.ts

@@ -704,7 +704,12 @@ export class SearchService {
               scheduleId: schedule.id,
             });
             return {
-              seatClassName:      fare.seatClassName,
+              // Use the input seat class name (sc.name) so it always matches what
+              // buildCoachTypeDetails looks up via coachType.seatClasses. The fare
+              // engine may resolve a nationality-specific variant (nationalitySeatClass)
+              // whose name differs from sc.name, which would cause the class to be
+              // silently dropped from coachTypes and show N/A on the results page.
+              seatClassName:      sc.name,
               baseFareMinor:      fare.totalMinor,
               displayCurrency:    fare.billingCurrency as Currency,
               displayAmountMinor: fare.totalInBillingCurrency,