feat: 跨平台持久化与版本管理优化

- Cookie 存储从 temp_dir 迁移至 Tauri app_data_dir，兼容 Linux
- 简单统一风格，UI优化
- recentLocal 播放历史持久化到 localStorage
- 添加设置界面可以修改简单的设置

src/stores/settings.ts

@@ -0,0 +1,86 @@
+import { defineStore } from 'pinia';
+import { ref, watch } from 'vue';
+
+export type AudioQuality = 'standard' | 'higher' | 'exhigh' | 'lossless' | 'hires';
+export type ThemeMode = 'dark' | 'light';
+export type CloseAction = 'ask' | 'minimize' | 'exit';
+
+export const qualityLabels: Record<AudioQuality, string> = {
+  standard: '标准',
+  higher: '较高',
+  exhigh: '极高 (HQ)',
+  lossless: '无损 (SQ)',
+  hires: 'Hi-Res',
+};
+
+export const closeActionLabels: Record<CloseAction, string> = {
+  ask: '每次询问',
+  minimize: '最小化到托盘',
+  exit: '直接退出',
+};
+
+interface SettingsData {
+  audioQuality: AudioQuality;
+  downloadPath: string;
+  theme: ThemeMode;
+  closeAction: CloseAction;
+}
+
+function loadSettings(): SettingsData {
+  try {
+    const raw = localStorage.getItem('app_settings');
+    if (raw) return JSON.parse(raw);
+  } catch {}
+  return {
+    audioQuality: 'standard',
+    downloadPath: '',
+    theme: 'dark',
+    closeAction: 'ask',
+  };
+}
+
+export const useSettingsStore = defineStore('settings', () => {
+  const saved = loadSettings();
+
+  const audioQuality = ref<AudioQuality>(saved.audioQuality);
+  const downloadPath = ref<string>(saved.downloadPath);
+  const theme = ref<ThemeMode>(saved.theme);
+  const closeAction = ref<CloseAction>(saved.closeAction || 'ask');
+
+  function setAudioQuality(q: AudioQuality) {
+    audioQuality.value = q;
+  }
+
+  function setDownloadPath(p: string) {
+    downloadPath.value = p;
+  }
+
+  function setTheme(t: ThemeMode) {
+    theme.value = t;
+  }
+
+  function setCloseAction(a: CloseAction) {
+    closeAction.value = a;
+  }
+
+  watch([audioQuality, downloadPath, theme, closeAction], () => {
+    const data: SettingsData = {
+      audioQuality: audioQuality.value,
+      downloadPath: downloadPath.value,
+      theme: theme.value,
+      closeAction: closeAction.value,
+    };
+    localStorage.setItem('app_settings', JSON.stringify(data));
+  }, { deep: true });
+
+  return {
+    audioQuality,
+    downloadPath,
+    theme,
+    closeAction,
+    setAudioQuality,
+    setDownloadPath,
+    setTheme,
+    setCloseAction,
+  };
+});