feat: 添加语言管理功能，更新系统设置页面，优化用户体验

src/App.vue

@@ -1,10 +1,15 @@
 <script setup lang="ts">
 const { initializeWallet } = useWalletStore();
+const { locale } = useLanguage();
 
 onMounted(() => {
   initializeWallet();
   console.log("App mounted successfully");
 });
+
+watch(locale, (newLocale) => {
+  document.querySelector("html")?.setAttribute("lang", newLocale);
+}, { immediate: true });
 </script>
 
 <template>