added find post by id on map

src/main/java/com/krylov/refound/service/PostService.java

@@ -381,4 +381,15 @@ public class PostService {
       throw new ApiException(ErrorCode.VALIDATION_ERROR, "Некорректный формат existingImages", HttpStatus.BAD_REQUEST);
     }
   }
+
+  public PostResponse getPostOnMapById(Long postId) {
+    Post post = postRepository.findById(postId)
+        .orElseThrow(() -> new ApiException(ErrorCode.NOT_FOUND, "Post not found", HttpStatus.NOT_FOUND));
+
+    List<Long> postIds = List.of(postId);
+    Map<Long, Long> likeCounts = countLikes(postIds);
+    Set<Long> userFavoriteIds = currentUserFavoriteIds(postIds);
+
+    return toResponse(post, likeCounts, userFavoriteIds, true);
+  }
 }