feat(listings): add featured boost to search and expose isFeatured in API responses

Featured listings now sort first in search results via featuredUntil desc ordering.
All listing read DTOs (detail, search, seller) include isFeatured boolean and featuredUntil timestamp.

Co-Authored-By: Paperclip <noreply@paperclip.ing>

apps/api/src/modules/listings/domain/repositories/listing-read.dto.ts

@@ -12,6 +12,8 @@ export interface ListingDetailData {
   viewCount: number;
   saveCount: number;
   inquiryCount: number;
+  isFeatured: boolean;
+  featuredUntil: string | null;
   publishedAt: string | null;
   createdAt: string;
   property: {
@@ -63,6 +65,8 @@ export interface ListingSearchItem {
   transactionType: TransactionType;
   priceVND: string;
   pricePerM2: number | null;
+  isFeatured: boolean;
+  featuredUntil: string | null;
   viewCount: number;
   publishedAt: string | null;
   property: {
@@ -92,6 +96,8 @@ export interface ListingSellerItem {
   status: ListingStatus;
   transactionType: TransactionType;
   priceVND: string;
+  isFeatured: boolean;
+  featuredUntil: string | null;
   property: {
     id: string;
     title: string;