fix: keep dock indicator distance constant when icons scale down

1. 修改指示器边距计算，对所有任务栏位置使用 Math.max()
2. 添加最小距离约束（iconSize/2 - 8）防止指示器过于靠近图标边缘
3. 对所有四个任务栏位置应用修复：顶部、底部、左侧、右侧
4. 确保图标缩小时指示器保持一致的视觉距离

Log: 修复图标缩小时任务栏指示器距离变得过小的问题

Influence:
1. 测试图标正常状态下的任务栏指示器显示
2. 验证悬停图标时指示器距离保持恒定
3. 在所有四个任务栏位置测试（顶部、底部、左侧、右侧）
4. 检查不同图标大小设置下的指示器定位
5. 验证不同屏幕分辨率下的视觉一致性

PMS: BUG-309165

Author: Ivy233

panels/dock/taskmanager/package/AppItem.qml

@@ -161,25 +161,25 @@ Item {
                 case Dock.Top: {
                     windowIndicator.anchors.horizontalCenter = iconContainer.horizontalCenter
                     windowIndicator.anchors.top = parent.top
-                    windowIndicator.anchors.topMargin = Qt.binding(() => {return (root.height - iconSize) / 2 / 3})
+                    windowIndicator.anchors.topMargin = Qt.binding(() => {return Math.max((root.height - iconSize) / 2 - 8, (root.height - iconSize) / 2 / 3)})
                     return
                 }
                 case Dock.Bottom: {
                     windowIndicator.anchors.horizontalCenter = iconContainer.horizontalCenter
                     windowIndicator.anchors.bottom = parent.bottom
-                    windowIndicator.anchors.bottomMargin = Qt.binding(() => {return (root.height - iconSize) / 2 / 3})
+                    windowIndicator.anchors.bottomMargin = Qt.binding(() => {return Math.max((root.height - iconSize) / 2 - 8, (root.height - iconSize) / 2 / 3)})
                     return
                 }
                 case Dock.Left: {
                     windowIndicator.anchors.verticalCenter = parent.verticalCenter
                     windowIndicator.anchors.left = parent.left
-                    windowIndicator.anchors.leftMargin = Qt.binding(() => {return (root.width - iconSize) / 2 / 3})
+                    windowIndicator.anchors.leftMargin = Qt.binding(() => {return Math.max((root.width - iconSize) / 2 - 8, (root.width - iconSize) / 2 / 3)})
                     return
                 }
                 case Dock.Right:{
                     windowIndicator.anchors.verticalCenter = parent.verticalCenter
                     windowIndicator.anchors.right = parent.right
-                    windowIndicator.anchors.rightMargin = Qt.binding(() => {return (root.width - iconSize) / 2 / 3})
+                    windowIndicator.anchors.rightMargin = Qt.binding(() => {return Math.max((root.width - iconSize) / 2 - 8, (root.width - iconSize) / 2 / 3)})
                     return
                 }
                 }