feat: 상품 상세에 랭킹 정보 추가

- ProductDetailInfo: ranking, brandId 필드 추가
- ProductReadService: brandId 설정
- ProductV1Dto: ranking 응답 필드 추가

Author: sylee6529

apps/commerce-api/src/main/java/com/loopers/application/product/ProductDetailInfo.java

@@ -14,16 +14,19 @@ public class ProductDetailInfo {
     private final Long id;
     private final String name;
     private final String description;
+    private final Long brandId;
     private final String brandName;
     private final String brandDescription;
     private final Money price;
     private final Stock stock;
     private final int likeCount;
     private final boolean isLikedByMember;
+    private final Integer ranking;  // 순위 (1-based), 순위권 밖이면 null
 
     public Long getId() { return id; }
     public String getName() { return name; }
     public String getDescription() { return description; }
+    public Long getBrandId() { return brandId; }
     public String getBrandName() { return brandName; }
     public String getBrandDescription() { return brandDescription; }
     public Money getPrice() { return price; }
@@ -33,6 +36,8 @@ public class ProductDetailInfo {
     @JsonProperty("likedByMember")
     public boolean isLikedByMember() { return isLikedByMember; }
 
+    public Integer getRanking() { return ranking; }
+
     @JsonPOJOBuilder(withPrefix = "")
     public static class ProductDetailInfoBuilder {
     }

apps/commerce-api/src/main/java/com/loopers/domain/product/service/ProductReadService.java

@@ -51,12 +51,14 @@ public ProductDetailInfo getProductDetail(Long productId, Long memberIdOrNull) {
                 .id(product.getId())
                 .name(product.getName())
                 .description(product.getDescription())
+                .brandId(product.getBrandId())
                 .brandName(brand.getName())
                 .brandDescription(brand.getDescription())
                 .price(product.getPrice())
                 .stock(product.getStock())
                 .likeCount(product.getLikeCount())
                 .isLikedByMember(isLikedByMember)
+                .ranking(null)  // 캐시 저장용, Facade에서 실시간 조회로 교체
                 .build();
     }
 

apps/commerce-api/src/main/java/com/loopers/interfaces/api/product/ProductV1Dto.java

@@ -39,7 +39,8 @@ public record ProductDetailResponse(
             BigDecimal price,
             int stockQuantity,
             int likeCount,
-            boolean isLikedByMember
+            boolean isLikedByMember,
+            Integer ranking  // 순위 (1-based), 순위권 밖이면 null
     ) {
         public static ProductDetailResponse from(ProductDetailInfo info) {
             return new ProductDetailResponse(
@@ -51,7 +52,8 @@ public static ProductDetailResponse from(ProductDetailInfo info) {
                     info.getPrice().getAmount(),
                     info.getStock().getQuantity(),
                     info.getLikeCount(),
-                    info.isLikedByMember()
+                    info.isLikedByMember(),
+                    info.getRanking()
             );
         }
     }