Add keyboard navigation to Location menu tree

[Copilot]

The Location menu (OneNotePicker) lacks arrow key navigation, preventing keyboard-only users and screen readers from accessing the notebook/section tree.

Changes

Added keyboard navigation handler to SectionPickerClass:

• Implements ARIA tree pattern: Up/Down navigate items, Right/Left expand/collapse or navigate hierarchy, Home/End jump to boundaries
• Queries [role="treeitem"] elements and manages focus based on visibility (skips collapsed items)
• Stores handler reference in component state for proper cleanup

Helper methods:

• isTreeItemVisible() - checks if item is visible (not in collapsed parent)
• isChildOf() - determines parent-child relationships in tree structure
• findParentTreeItem() - traverses DOM to find parent tree item

Implementation:

handlePickerKeyboardNavigation(element: HTMLElement, isFirstDraw: boolean) {
  // Clean up existing handler
  if (this.state.keyboardNavigationHandler) {
    document.removeEventListener("keydown", this.state.keyboardNavigationHandler, true);
  }
  
  const keydownHandler = (e: KeyboardEvent) => {
    const treeItems = document.querySelectorAll('[role="treeitem"]');
    // Navigate based on KeyCodes.up/down/left/right/home/end
    // Focus appropriate item, prevent default scroll behavior
  };
  
  this.setState({ keyboardNavigationHandler: keydownHandler });
  document.addEventListener("keydown", keydownHandler, true);
}

The OneNotePicker library already uses correct ARIA attributes (role="tree", role="treeitem", aria-expanded) but only handled Enter key. This adds full keyboard support at the integration layer without modifying the third-party library.

Original prompt

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This section details on the original issue you should resolve

<issue_title>Test</issue_title>
<issue_description>Environment & OS Details:

Application Name: OneNote Clipper
URL: -OneNote Web Clipper Installation
Chromium Edge Dev: - Version 110.0.1556.0 (Official build) dev (64-bit)
Application version: Version 3.8.9
Repro Steps:
Open OneNote Web Clipper Installation Application.
Tab till 'OneNote Clipper' extension.
Check Whether The list and the nested list items, after expanding the “Location” menu button is not being access with the help of “Arrow” key. or not.
Actual:
In region, Narrator is not announcing anything while trying to capture the screen to clip with the help of “Arrow” key.
Expected:
In region, Narrator is not announcing anything while trying to capture the screen to clip with the help of “Arrow” key.
User Experience:
Users with No vision will not be able to clip the captured screen if proper announcement is not available.
MAS Reference:
MAS 4.3.1 – No Disruption of Accessibility Features</issue_description>

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

• Fixes Test #599

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