Add i18 support

frontend/src/hooks/useLanguageSwitcher.ts

@@ -0,0 +1,30 @@
+import { useCallback } from 'react';
+import { useTranslation } from 'react-i18next';
+import { useUIStore } from '../stores/ui.store';
+import { type SupportedLanguage } from '../locales';
+
+/**
+ * Hook for managing language switching with proper synchronization
+ * between i18n and UI store
+ */
+export function useLanguageSwitcher() {
+  const { i18n } = useTranslation();
+  const { language: uiLanguage, setLanguage: setUILanguage } = useUIStore();
+
+  const changeLanguage = useCallback(async (newLanguage: SupportedLanguage) => {
+    try {
+      // Only change i18n language - let the i18n event handler update UI store
+      await i18n.changeLanguage(newLanguage);
+    } catch (error) {
+      console.error('Failed to change language:', error);
+    }
+  }, [i18n]);
+
+  const isChanging = i18n.isLanguageChangingTo !== false;
+
+  return {
+    currentLanguage: i18n.language as SupportedLanguage,
+    changeLanguage,
+    isChanging,
+  };
+}