fix: UI 语义区分会话总量与日月累计 + 修复 onVisibleChanged 重复

弹窗'流量总计'改为'本次会话'，明确是本次 dde-shell 运行期间累计；
流量统计窗口'按接口累计'改为'今日累计/本月累计'，明确是跨重启持久化。
修复 TrafficStatsWindow onVisibleChanged 重复设置导致插件加载失败

package/components/NetworkPopup.qml

@@ -454,7 +454,7 @@ Control {
             Item { Layout.fillWidth: true }
 
             Text {
-                text: qsTr("Total")
+                text: qsTr("Session Total")
                 font.pixelSize: 12
                 color: popup.tertiaryText
             }

package/components/TrafficStatsWindow.qml

@@ -211,7 +211,7 @@ Window {
 
                 // 右侧数据说明：按接口累计
                 Text {
-                    text: qsTr("Accumulated by interface")
+                    text: root.currentTab === 0 ? qsTr("Today accumulated") : qsTr("This month accumulated")
                     font.pixelSize: 11
                     color: theme.textTertiary
                 }

translations/jnetapplet_zh_CN.ts

@@ -78,8 +78,8 @@
     </message>
     <message>
         <location filename="../package/components/NetworkPopup.qml" line="427"/>
-        <source>Total</source>
-        <translation>流量总计</translation>
+        <source>Session Total</source>
+        <translation>本次会话</translation>
     </message>
     <message>
         <location filename="../package/components/NetworkPopup.qml" line="474"/>
@@ -295,8 +295,13 @@
     </message>
     <message>
         <location filename="../package/components/TrafficStatsWindow.qml" line="202"/>
-        <source>Accumulated by interface</source>
-        <translation>按接口累计</translation>
+        <source>Today accumulated</source>
+        <translation>今日累计</translation>
+    </message>
+    <message>
+        <location filename="../package/components/TrafficStatsWindow.qml" line="214"/>
+        <source>This month accumulated</source>
+        <translation>本月累计</translation>
     </message>
     <message>
         <location filename="../package/components/TrafficStatsWindow.qml" line="218"/>