Add generic TreeView<T> control to support custom metadata on tree items

[Copilot]

• Create TreeViewItem wrapper class to attach metadata to TreeViewItem objects
• Create TreeView generic control similar to DropDown and CheckBoxList
• Update events to work with TreeViewItem instead of raw TreeViewItem
• Add methods to convert between TreeViewItem and TreeViewItem
• Add extension methods for TreeView in UiResultsExtensions
• Add tests for the new generic TreeView control (including edge cases)
• Add parameterless constructor to TreeView
• Build and test the implementation
• Run security checks

Implementation Complete

Successfully implemented a generic TreeView<T> control for the Interactive Automation Script Toolkit. The implementation follows the established pattern of existing generic controls (DropDown, CheckBoxList, RadioButtonList).

Recent Update:

Added parameterless constructor to TreeView following the same pattern as other generic controls, allowing developers to instantiate the control without immediately assigning items.

Key Features:

• TreeViewItemOption: Wrapper class that associates custom metadata with TreeViewItem objects
• TreeView: Generic tree view control with full support for hierarchical data
• Parameterless Constructor: Can now instantiate without immediately assigning items
• Type-safe API: Allows developers to attach strongly-typed metadata to tree items
• Events: All events (Changed, Checked, Unchecked, Expanded, Collapsed) work with TreeViewItemOption
• Helper methods: GetAllItems(), GetItems(depth), TryFindTreeViewItem(), CheckedValues, CheckedLeaves, CheckedNodes, etc.

All builds pass successfully, comprehensive tests are in place, and CodeQL security checks show no issues.

Original prompt

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This section details on the original issue you should resolve

<issue_title>Generic implementation of TreeView control</issue_title>
<issue_description>Add a generic version of the TreeView control to the toolkit: TreeView, similar to DropDown, CheckBoxList and RadioButtonList.
This would allow to attach custom metadata to each TreeViewItem, where T is the type of that custom data.
</issue_description>

Comments on the Issue (you are @copilot in this section)

Fixes #43

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[TomW-Skyline]

@copilot also add a parameterless constructor so that it can be used without immediately assigning items to it.

[Copilot]

@copilot also add a parameterless constructor so that it can be used without immediately assigning items to it.

Added parameterless constructor following the same pattern as DropDown and CheckBoxList. The constructor calls the existing constructor with an empty enumerable. Commit: 456be1f