feat(client): add Traditional Chinese (zh-TW) language support

packages/client/src/components/layout/LanguageSwitch.vue

@@ -5,7 +5,8 @@ import { NSelect } from 'naive-ui'
 const { locale } = useI18n()
 
 const options = [
-  { label: '中文', value: 'zh' },
+  { label: '简体中文', value: 'zh' },
+  { label: '繁體中文', value: 'zh-TW' },
   { label: 'English', value: 'en' },
   { label: '日本語', value: 'ja' },
   { label: '한국어', value: 'ko' },

packages/client/src/i18n/index.ts

@@ -2,24 +2,45 @@ import { createI18n } from 'vue-i18n'
 import { messages } from './messages'
 
 const saved = localStorage.getItem('hermes_locale')
-const detected = navigator.language.slice(0, 2)
 
-const supportedLocales = ['en', 'zh', 'ja', 'ko', 'fr', 'es', 'de', 'pt'] as const
+const supportedLocales = ['en', 'zh', 'zh-TW', 'ja', 'ko', 'fr', 'es', 'de', 'pt'] as const
 type SupportedLocale = (typeof supportedLocales)[number]
 
-function resolveLocale(saved: string | null, detected: string): SupportedLocale {
+function resolveLocale(saved: string | null): SupportedLocale {
   if (saved && (supportedLocales as readonly string[]).includes(saved)) {
     return saved as SupportedLocale
   }
-  if ((supportedLocales as readonly string[]).includes(detected)) {
-    return detected as SupportedLocale
+
+  // Normalize a single BCP-47 tag to a supported locale key.
+  // Covers zh-Hant-TW, zh-TW, zh-HK, zh-MO, zh-Hant → zh-TW
+  //        zh-Hans-*, zh-CN, zh-SG, zh            → zh
+  function normalize(tag: string): SupportedLocale | null {
+    const lower = tag.toLowerCase()
+    if (lower.startsWith('zh')) {
+      const isTraditional =
+        lower.includes('hant') ||
+        lower.includes('-tw') ||
+        lower.includes('-hk') ||
+        lower.includes('-mo')
+      return isTraditional ? 'zh-TW' : 'zh'
+    }
+    const short = tag.slice(0, 2)
+    if ((supportedLocales as readonly string[]).includes(tag)) return tag as SupportedLocale
+    if ((supportedLocales as readonly string[]).includes(short)) return short as SupportedLocale
+    return null
+  }
+
+  for (const lang of navigator.languages) {
+    const resolved = normalize(lang)
+    if (resolved) return resolved
   }
+
   return 'en'
 }
 
 export const i18n = createI18n({
   legacy: false,
-  locale: resolveLocale(saved, detected),
+  locale: resolveLocale(saved),
   fallbackLocale: 'en',
   messages,
 })