feat: render Japanese short description on heritage detail

Branch on locale in the overview section to show shortDescriptionJp when ja
locale is active, falling back to the English shortDescription otherwise.
Plumb locale through HeritageDetailLayout and update fixtures accordingly.

Author: zigzagdev

client/src/app/features/heritages/mappers/__tests__/to-world-heritage-vm.test.ts

@@ -19,6 +19,7 @@ const base: ApiWorldHeritageDto = {
   area_hectares: 442,
   buffer_zone_hectares: 320,
   short_description: "desc",
+  short_description_jp: "ダミー",
   unesco_site_url: "https://whc.unesco.org/en/list/663",
   state_party: "JPN",
   state_party_codes: ["JPN"],

client/src/app/features/top/components/heritage-detail/HeritageDetailLayout.tsx

@@ -145,7 +145,7 @@ export function HeritageDetailLayout({ item, locale, toggleLocale }: Props) {
         <div className="grid gap-6 lg:gap-8 lg:grid-cols-[minmax(0,1fr)_360px] lg:items-start">
           {/* Left: Overview → Gallery */}
           <div className="space-y-8" id="content">
-            <HeritageOverViewSection item={item} />
+            <HeritageOverViewSection item={item} locale={locale} />
             <HeritageGallery images={item.images} />
           </div>
 

client/src/app/features/top/components/heritage-detail/HeritageOverviewSection.tsx

@@ -3,9 +3,10 @@ import { textType } from "@shared/styles/typography.ts";
 
 type Props = {
   item: WorldHeritageDetailVm;
+  locale: string;
 };
 
-export function HeritageOverViewSection({ item }: Props) {
+export function HeritageOverViewSection({ item, locale }: Props) {
   return (
     <section
       id="overview"
@@ -31,7 +32,9 @@ export function HeritageOverViewSection({ item }: Props) {
 
       {item.shortDescription ? (
         <p className={`${textType.body} ${textType.measure} mt-4 whitespace-pre-wrap`}>
-          {item.shortDescription}
+          {locale === "ja" && item.shortDescriptionJp
+            ? item.shortDescriptionJp
+            : item.shortDescription}
         </p>
       ) : (
         <p className={`${textType.body} mt-4 text-zinc-400`}>—</p>

client/src/app/features/top/containers/__tests__/world-heritage-detail-container.test.tsx

@@ -145,6 +145,7 @@ describe("WorldHeritageDetailContainer", () => {
       latitude: null,
       longitude: null,
       shortDescription: "dummy",
+      shortDescriptionJp: "ダミー",
       unescoSiteUrl: "https://example.com",
       statePartyCodes: [],
       statePartiesMeta: {},