refactor: unify app split/merge display and optimize text calculation

1. Replaced separate AppItemWithTitle.qml with unified AppItem.qml that
handles both split and merged window modes
2. Introduced TextCalculator C++ class to handle dynamic text width
calculation for better performance
3. Created AppItemTitle.qml as a reusable component for displaying
application titles with proper elision
4. Removed complex QML-based text width calculations and dynamic
character limit arrays
5. Simplified TaskManager.qml by moving text calculation logic to C+
+ backend
6. Improved window split mode handling with more accurate space
allocation calculations

Log: Unified application split and merge display into single item view

Influence:
1. Test application display in both split and merged window modes
2. Verify text elision works correctly with long application titles
3. Check performance when multiple applications are open with window
split enabled
4. Test drag and drop functionality between applications
5. Verify application title visibility in different dock positions
6. Test window preview and context menu functionality
7. Check memory usage with many open applications

refactor: 统一应用拆分/合并显示并优化文本计算

1. 将单独的 AppItemWithTitle.qml 替换为统一的 AppItem.qml，同时处理拆分
和合并窗口模式
2. 引入 TextCalculator C++ 类来处理动态文本宽度计算，提高性能
3. 创建 AppItemTitle.qml 作为可重用组件，用于显示带正确省略的应用标题
4. 移除复杂的基于 QML 的文本宽度计算和动态字符限制数组
5. 通过将文本计算逻辑移至 C++ 后端简化 TaskManager.qml
6. 改进窗口拆分模式处理，提供更准确的空间分配计算

Log: 将应用拆分和合并显示统一为单一项视图

Influence:
1. 测试应用在拆分和合并窗口模式下的显示
2. 验证长应用标题的文本省略功能是否正常工作
3. 检查启用窗口拆分时多个应用打开的性能
4. 测试应用之间的拖放功能
5. 验证不同任务栏位置下应用标题的可见性
6. 测试窗口预览和上下文菜单功能
7. 检查打开多个应用时的内存使用情况

PMS: TASK-384101

Author: 18202781743

panels/dock/package/main.qml

@@ -25,6 +25,7 @@ Window {
     property int dockRemainingSpaceForCenter: useColumnLayout ?
         (Screen.height / 1.8 - dockRightPart.implicitHeight)  :
         (Screen.width / 1.8 - dockRightPart.implicitWidth) 
+    property int dockPartSpacing: gridLayout.columnSpacing
     // TODO
     signal dockCenterPartPosChanged()
     signal pressedAndDragging(bool isDragging)

panels/dock/taskmanager/CMakeLists.txt

@@ -84,6 +84,8 @@ add_library(dock-taskmanager SHARED ${DBUS_INTERFACES}
     treelandwindowmonitor.h
     taskmanagersettings.cpp
     taskmanagersettings.h
+    textcalculator.h
+    textcalculator.cpp
 )
 
 qt_generate_wayland_protocol_client_sources(dock-taskmanager