feat: 参照dde-weather重构插件，修复显示与弹窗定位

- QML 根元素使用 AppletItem，参照 dde-weather 插件实现
- 使用 Panel.rootObject.dockItemMaxSize 适配任务栏图标尺寸
- dockOrder 设为 21，定位在系统托盘左侧
- 使用 PanelPopup + PanelToolTip + TapHandler 实现点击弹窗和悬停提示
- 弹窗打开前设置 DockPanelPositioner.bounding 修正弹窗定位
- C++ 后端新增 dbusAvailable 属性，D-Bus 不可用时优雅降级
- 使用 isServiceRegistered 正确检测 D-Bus 服务可用性
- install.sh 改用 SCRIPT_DIR 自动定位项目根目录

graphicsdriverapplet.cpp

@@ -6,6 +6,7 @@
 #include <pluginfactory.h>
 
 #include <QDBusConnection>
+#include <QDBusConnectionInterface>
 #include <QDBusPendingReply>
 #include <QDebug>
 #include <QJsonDocument>
@@ -26,6 +27,7 @@ GraphicsDriverApplet::GraphicsDriverApplet(QObject *parent)
     , m_progressTimer(new QTimer(this))
     , m_installProgress(0)
     , m_isInstalling(false)
+    , m_dbusAvailable(false)
 {
 }
 
@@ -36,15 +38,14 @@ GraphicsDriverApplet::~GraphicsDriverApplet()
 bool GraphicsDriverApplet::load()
 {
     initDBusConnection();
-    connect(m_progressTimer, &QTimer::timeout, [this]() {
-        // Poll progress
-    });
     return DApplet::load();
 }
 
 bool GraphicsDriverApplet::init()
 {
-    refreshDeviceInfo();
+    if (m_dbusAvailable) {
+        refreshDeviceInfo();
+    }
     return DApplet::init();
 }
 
@@ -68,6 +69,11 @@ bool GraphicsDriverApplet::isInstalling() const
     return m_isInstalling;
 }
 
+bool GraphicsDriverApplet::dbusAvailable() const
+{
+    return m_dbusAvailable;
+}
+
 void GraphicsDriverApplet::refreshDeviceInfo()
 {
     if (!m_dbusInterface || !m_dbusInterface->isValid()) {
@@ -215,6 +221,13 @@ void GraphicsDriverApplet::initDBusConnection()
         return;
     }
 
+    // 检查服务是否已注册
+    bool registered = bus.interface()->isServiceRegistered(DBUS_SERVICE);
+    if (!registered) {
+        qWarning() << "GraphicsDriver D-Bus service is not registered";
+        return;
+    }
+
     m_dbusInterface = new QDBusInterface(
         DBUS_SERVICE,
         DBUS_PATH,
@@ -228,8 +241,13 @@ void GraphicsDriverApplet::initDBusConnection()
         return;
     }
 
+    m_dbusAvailable = true;
+    emit dbusAvailableChanged();
+
     connect(m_dbusInterface, SIGNAL(ReportProgress(QString)),
             this, SLOT(onReportProgress(QString)));
+
+    qDebug() << "GraphicsDriver D-Bus connected successfully";
 }
 
 void GraphicsDriverApplet::setInstalling(bool installing)