📝 add Chinese API guides and locale detection

docs/.vitepress/theme/index.ts

@@ -6,11 +6,46 @@ import HomeDocHub from './components/HomeDocHub.vue'
 
 import './custom.css'
 
+const localePreferenceKey = 'bitlogger-docs-locale'
+
+function routePath(path: string): string {
+  return path.split(/[?#]/, 1)[0]
+}
+
+function isLocaleRoot(path: string): boolean {
+  const normalized = routePath(path)
+  return normalized === '/' || normalized === '/zh/'
+}
+
+function browserPrefersChinese(): boolean {
+  return navigator.languages.some(language => language.toLowerCase().startsWith('zh'))
+}
+
 const theme: Theme = {
   extends: DefaultTheme,
-  enhanceApp({ app }) {
+  enhanceApp({ app, router }) {
     app.component('ApiOverview', ApiOverview)
     app.component('HomeDocHub', HomeDocHub)
+
+    if (typeof window === 'undefined') return
+
+    router.onAfterRouteChange = to => {
+      if (!isLocaleRoot(to)) return
+      window.localStorage.setItem(localePreferenceKey, routePath(to) === '/zh/' ? 'zh' : 'en')
+    }
+
+    if (router.route.path !== '/') return
+
+    const savedLocale = window.localStorage.getItem(localePreferenceKey)
+    const locale = savedLocale === 'zh' || savedLocale === 'en'
+      ? savedLocale
+      : browserPrefersChinese()
+        ? 'zh'
+        : 'en'
+
+    if (locale === 'zh') {
+      void router.go('/zh/')
+    }
   },
 }