feat(i18n): add full ja/vi/id/ms translations and drop languageNames fallback

- Add complete dicts: src/locales/{ja,vi,id,ms}.ts (115 keys each)
- Remove languageNames override map; dict object now points directly to each locale
- i18n.tsx shrinks from ~414 lines to ~81 lines

src/i18n.tsx

@@ -9,99 +9,22 @@ import { languageForHomePathname } from "./languageRoutes";
 import type { Dict } from "./locales/types";
 import { zhDict } from "./locales/zh-CN";
 import { enDict } from "./locales/en";
+import { jaDict } from "./locales/ja";
 import { koDict } from "./locales/ko";
+import { viDict } from "./locales/vi";
+import { idDict } from "./locales/id";
+import { msDict } from "./locales/ms";
 
 export type Lang = "zh-CN" | "en" | "ja" | "ko" | "vi" | "id" | "ms";
 
-const languageNames: Record<Lang, Dict> = {
-  "zh-CN": {
-    lang_zh_CN: "中文",
-    lang_en: "English",
-    lang_ja: "日本語",
-    lang_ko: "한국어",
-    lang_vi: "Tiếng Việt",
-    lang_id: "Bahasa Indonesia",
-    lang_ms: "Bahasa Melayu",
-  },
-  en: {
-    lang_zh_CN: "Chinese",
-    lang_en: "English",
-    lang_ja: "Japanese",
-    lang_ko: "Korean",
-    lang_vi: "Vietnamese",
-    lang_id: "Indonesian",
-    lang_ms: "Malay",
-  },
-  ja: {
-    brand: "ARK ライブラリー",
-    showMore: "すべて表示",
-    showLess: "閉じる",
-    lang_zh_CN: "中国語",
-    lang_en: "英語",
-    lang_ja: "日本語",
-    lang_ko: "韓国語",
-    lang_vi: "ベトナム語",
-    lang_id: "インドネシア語",
-    lang_ms: "マレー語",
-  },
-  ko: {
-    brand: "ARK 라이브러리",
-    showMore: "모두 보기",
-    showLess: "접기",
-    lang_zh_CN: "중국어",
-    lang_en: "영어",
-    lang_ja: "일본어",
-    lang_ko: "한국어",
-    lang_vi: "베트남어",
-    lang_id: "인도네시아어",
-    lang_ms: "말레이어",
-  },
-  vi: {
-    brand: "Thư viện ARK",
-    showMore: "Xem tất cả",
-    showLess: "Thu gọn",
-    lang_zh_CN: "Tiếng Trung",
-    lang_en: "Tiếng Anh",
-    lang_ja: "Tiếng Nhật",
-    lang_ko: "Tiếng Hàn",
-    lang_vi: "Tiếng Việt",
-    lang_id: "Tiếng Indonesia",
-    lang_ms: "Tiếng Mã Lai",
-  },
-  id: {
-    brand: "Perpustakaan ARK",
-    showMore: "Lihat semua",
-    showLess: "Tutup",
-    lang_zh_CN: "Bahasa Tionghoa",
-    lang_en: "Bahasa Inggris",
-    lang_ja: "Bahasa Jepang",
-    lang_ko: "Bahasa Korea",
-    lang_vi: "Bahasa Vietnam",
-    lang_id: "Bahasa Indonesia",
-    lang_ms: "Bahasa Melayu",
-  },
-  ms: {
-    brand: "Perpustakaan ARK",
-    showMore: "Lihat semua",
-    showLess: "Tutup",
-    lang_zh_CN: "Bahasa Cina",
-    lang_en: "Bahasa Inggeris",
-    lang_ja: "Bahasa Jepun",
-    lang_ko: "Bahasa Korea",
-    lang_vi: "Bahasa Vietnam",
-    lang_id: "Bahasa Indonesia",
-    lang_ms: "Bahasa Melayu",
-  },
-};
-
 const dict: Record<Lang, Dict> = {
-  "zh-CN": { ...zhDict, ...languageNames["zh-CN"] },
-  en: { ...enDict, ...languageNames.en },
-  ja: { ...enDict, ...languageNames.ja },
+  "zh-CN": zhDict,
+  en: enDict,
+  ja: jaDict,
   ko: koDict,
-  vi: { ...enDict, ...languageNames.vi },
-  id: { ...enDict, ...languageNames.id },
-  ms: { ...enDict, ...languageNames.ms },
+  vi: viDict,
+  id: idDict,
+  ms: msDict,
 };
 
 /** Fixed locale lookup (admin UI uses Simplified Chinese). */