style(hotspot): optimize hotspot dialog UI appearance

Add transparent background to hotspot dialog and change save button
to recommended button style for better visual consistency.

优化热点对话框UI外观，添加透明背景并将保存按钮改为推荐按钮样式。

Log: 优化热点对话框UI
PMS: BUG-316567
Influence: 热点对话框界面更加美观统一，提升用户体验。

Author: add-uos

dcc-network/qml/PageHotspot.qml

@@ -209,6 +209,7 @@ DccObject {
 
                     modality: Qt.ApplicationModal
                     width: 380
+                    color: "transparent"
                     icon: "preferences-system"
                     onClosing: destroy()
                     ColumnLayout {
@@ -341,7 +342,7 @@ DccObject {
                                 color: this.palette.button
                             }
 
-                            D.Button {
+                            D.RecommandButton {
                                 Layout.fillWidth: true
                                 // contentItem: D.IconLabel {
                                 text: qsTr("Save")