实现 CT 时间偏移选择并优化 URL 语言处理：新增获取 CT 时间偏移选项接口，表单改用下拉选择；URL 语言参数统一为 zh/tw/en 并兼容旧版；Vite 支持局域网访问，更新开发文档。

src/config/appLocale.ts

@@ -2,8 +2,48 @@ export const APP_LOCALES = ['zh-CN', 'zh-TW', 'en-US'] as const
 
 export type AppLocale = (typeof APP_LOCALES)[number]
 
+/** URL `lang` 查询参数取值（写入地址栏时使用） */
+export const URL_LANG_CODES = ['zh', 'tw', 'en'] as const
+
+export type UrlLangCode = (typeof URL_LANG_CODES)[number]
+
 export const DEFAULT_LOCALE: AppLocale = 'zh-TW'
 
+export const DEFAULT_URL_LANG: UrlLangCode = 'tw'
+
+export const LOCALE_TO_URL_LANG: Record<AppLocale, UrlLangCode> = {
+  'zh-CN': 'zh',
+  'zh-TW': 'tw',
+  'en-US': 'en',
+}
+
+const URL_LANG_TO_LOCALE: Record<UrlLangCode, AppLocale> = {
+  zh: 'zh-CN',
+  tw: 'zh-TW',
+  en: 'en-US',
+}
+
 export function isAppLocale(value: string | null): value is AppLocale {
   return value !== null && (APP_LOCALES as readonly string[]).includes(value)
 }
+
+/** 解析 URL / 用户输入的语言参数为内部 `AppLocale` */
+export function resolveLocaleFromLangParam(value: string | undefined): AppLocale {
+  if (!value) {
+    return DEFAULT_LOCALE
+  }
+  const trimmed = value.trim()
+  const lower = trimmed.toLowerCase()
+  if ((URL_LANG_CODES as readonly string[]).includes(lower)) {
+    return URL_LANG_TO_LOCALE[lower as UrlLangCode]
+  }
+  const normalized = trimmed.replace('_', '-')
+  if (isAppLocale(normalized)) {
+    return normalized
+  }
+  return DEFAULT_LOCALE
+}
+
+export function localeToUrlLang(locale: AppLocale): UrlLangCode {
+  return LOCALE_TO_URL_LANG[locale]
+}

src/config/urlPreferences.ts

@@ -1,5 +1,5 @@
 import type { LocationQuery } from 'vue-router'
-import { DEFAULT_LOCALE, isAppLocale, type AppLocale } from '@/config/appLocale'
+import { localeToUrlLang, resolveLocaleFromLangParam, type AppLocale } from '@/config/appLocale'
 import { APP_THEMES, DEFAULT_THEME, type AppTheme } from '@/theme/types'
 
 export const URL_PARAM_LANG = 'lang'
@@ -37,14 +37,7 @@ function normalizeTheme(value: string | undefined): AppTheme {
 }
 
 function normalizeLocale(value: string | undefined): AppLocale {
-  if (!value) {
-    return DEFAULT_LOCALE
-  }
-  const normalized = value.replace('_', '-')
-  if (isAppLocale(normalized)) {
-    return normalized
-  }
-  return DEFAULT_LOCALE
+  return resolveLocaleFromLangParam(value)
 }
 
 export function parsePreferencesFromSearch(search: string): AppPreferences {
@@ -82,7 +75,7 @@ export function preferencesToQuery(
       }
     }
   }
-  next[URL_PARAM_LANG] = preferences.locale
+  next[URL_PARAM_LANG] = localeToUrlLang(preferences.locale)
   next[URL_PARAM_THEME] = preferences.theme
   return next
 }