feat: GPU切换回退保护逻辑

- switchGpu切换前写入备份文件(.gpu-switch-backup)记录之前模式
- init()检测未确认的切换，启动30秒自动回退计时器
- QML弹出'显示是否正常'确认覆盖层，支持手动确认/回退/超时自动回退
- confirmSwitchSuccess()用户确认正常后删除备份
- restoreFromBackup()自动恢复之前模式并发送通知
- primeOffloadEnabled属性检测当前PRIME offload状态
- switchGpu改用environment.d方式，不需要root/pkexec
- 翻译更新：回退确认相关8条新增

graphicsdriverapplet.h

@@ -47,6 +47,9 @@ class GraphicsDriverApplet : public DApplet
     Q_PROPERTY(QVariantList tempHistory READ tempHistory NOTIFY tempHistoryChanged)
     Q_PROPERTY(QStringList gpuProcesses READ gpuProcesses NOTIFY gpuProcessesChanged)
     Q_PROPERTY(bool tempAlertEnabled READ tempAlertEnabled WRITE setTempAlertEnabled NOTIFY tempAlertEnabledChanged)
+    Q_PROPERTY(bool primeOffloadEnabled READ primeOffloadEnabled NOTIFY primeOffloadEnabledChanged)
+    Q_PROPERTY(bool switchPending READ switchPending NOTIFY switchPendingChanged)
+    Q_PROPERTY(int restoreCountdown READ restoreCountdown NOTIFY restoreCountdownChanged)
 
 public:
     explicit GraphicsDriverApplet(QObject *parent = nullptr);
@@ -66,10 +69,15 @@ public:
     QStringList gpuProcesses() const;
     bool tempAlertEnabled() const;
     void setTempAlertEnabled(bool enabled);
+    bool primeOffloadEnabled() const;
+    bool switchPending() const;
+    int restoreCountdown() const;
 
     Q_INVOKABLE void refreshDeviceInfo();
     Q_INVOKABLE void refreshStats();
     Q_INVOKABLE bool switchGpu(const QString &mode);
+    Q_INVOKABLE void confirmSwitchSuccess();
+    Q_INVOKABLE void restoreSwitch();
 
 signals:
     void deviceInfoChanged();
@@ -82,6 +90,9 @@ signals:
     void tempHistoryChanged();
     void gpuProcessesChanged();
     void tempAlertEnabledChanged();
+    void primeOffloadEnabledChanged();
+    void switchPendingChanged();
+    void restoreCountdownChanged();
 
 private:
     void detectGpus();
@@ -90,6 +101,9 @@ private:
     void detectGpuMode();
     void checkTempAlert();
     void sendNotification(const QString &summary, const QString &body);
+    void restoreFromBackup();
+    static QString primeConfigPath();
+    static QString backupFilePath();
     static int findDrmCard(const QString &pciId);
     static QStringList runCommand(const QString &cmd, const QStringList &args);
     static QString parseGpuName(const QString &line);
@@ -110,6 +124,9 @@ private:
     // 温度告警冷却时间戳
     qint64 m_lastAlertTime;
     bool m_tempAlertEnabled;
+    bool m_switchPending;
+    int m_restoreCountdown;
+    QTimer *m_restoreTimer;
 };
 
 DS_END_NAMESPACE