feat: added French support

src/i18n/locale.ts

@@ -1,13 +1,14 @@
 import type { LanguageSetting, ResolvedLocaleCode } from './types';
 
 const CHINESE_LANGUAGE_PREFIX = 'zh';
+const FRENCH_LANGUAGE_PREFIX = 'fr';
 const DEFAULT_LOCALE: ResolvedLocaleCode = 'en_us';
 
 // BCP 47 subtags that indicate Traditional Chinese (Hant script or HK/TW/MO regions)
 const TRADITIONAL_CHINESE_SUBTAGS = new Set(['hk', 'tw', 'mo', 'hant']);
 
 export function normalizeLanguageSetting(value: unknown): LanguageSetting {
-  return value === 'zh_cn' || value === 'en_us' || value === 'zh_hk' || value === 'auto' ? value : 'auto';
+  return value === 'zh_cn' || value === 'en_us' || value === 'zh_hk' || value === 'fr_fr' || value === 'auto' ? value : 'auto';
 }
 
 export function getBrowserLocales(): string[] {
@@ -28,7 +29,7 @@ export function resolveLanguageSetting(
   setting: LanguageSetting,
   browserLocales: string[] = getBrowserLocales(),
 ): ResolvedLocaleCode {
-  if (setting === 'en_us' || setting === 'zh_cn' || setting === 'zh_hk') {
+  if (setting === 'en_us' || setting === 'zh_cn' || setting === 'zh_hk' || setting === 'fr_fr') {
     return setting;
   }
 
@@ -42,6 +43,9 @@ export function resolveLanguageSetting(
       const isTraditional = subtags.some((tag) => TRADITIONAL_CHINESE_SUBTAGS.has(tag));
       return isTraditional ? 'zh_hk' : 'zh_cn';
     }
+    if (normalizedLocale === FRENCH_LANGUAGE_PREFIX || normalizedLocale.startsWith(`${FRENCH_LANGUAGE_PREFIX}-`)) {
+      return 'fr_fr';
+    }
   }
 
   return DEFAULT_LOCALE;