feat: 添加语言管理功能，更新系统设置页面，优化用户体验

src/composables/useLanguage.ts

@@ -0,0 +1,60 @@
+import type { Locale } from "vue-i18n";
+
+export interface Language {
+  code: Locale;
+  name: string;
+  nativeName: string;
+}
+
+/**
+ * 语言管理组合式函数
+ */
+export function useLanguage() {
+  const { locale, availableLocales } = useI18n();
+
+  // 可用的语言列表
+  const languages: Language[] = [
+    {
+      code: "zh-CN",
+      name: "Chinese (Simplified)",
+      nativeName: "简体中文",
+    },
+    {
+      code: "en-US",
+      name: "English (US)",
+      nativeName: "English",
+    },
+  ];
+
+  // 当前语言
+  const currentLanguage = computed(() => {
+    return languages.find(lang => lang.code === locale.value) || languages[0];
+  });
+
+  /**
+   * 切换语言
+   */
+  function setLanguage(langCode: Locale) {
+    locale.value = langCode;
+    // 持久化到 localStorage
+    localStorage.setItem("app-language", langCode);
+  }
+
+  /**
+   * 从 localStorage 加载保存的语言
+   */
+  function loadSavedLanguage() {
+    const saved = localStorage.getItem("app-language") as Locale;
+    if (saved && availableLocales.includes(saved)) {
+      locale.value = saved;
+    }
+  }
+
+  return {
+    languages,
+    currentLanguage,
+    locale,
+    setLanguage,
+    loadSavedLanguage,
+  };
+}