Add an option to display Copilot-edited files in either List View or Tree View

## Title

Add an option to display Copilot-edited files in either List View or Tree View

## Feature Request

When GitHub Copilot completes a task that modifies multiple files, it displays the edited files in a flat list.

The existing flat list is useful, but it would be helpful to also provide an optional **Tree View** that groups the modified files according to the workspace or project folder structure.

This could work similarly to the VS Code Source Control sidebar, where users can choose between a flat list layout and a tree-based layout.

## Current Behaviour

Copilot displays all modified files in a flat list, for example:

```text
Button.tsx
Button.module.scss
index.ts
Header.tsx
Header.module.scss
```

In larger projects, monorepos, or deeply nested folder structures, it can be difficult to understand where each modified file is located.

## Proposed Behaviour

Provide a view selector that allows users to switch between:

* **List View** — the existing flat list
* **Tree View** — files grouped by their project folder structure

For example, the Tree View could display:

```text
src/
├── components/
│ ├── Button/
│ │ ├── Button.tsx
│ │ ├── Button.module.scss
│ │ └── index.ts
│ └── Header/
│ ├── Header.tsx
│ └── Header.module.scss
```

The view selector could be similar to the List View and Tree View options available in the VS Code GIT extension , shows changed files can show the files in both option(based on what is elect as view for me)

## Additional Context

I have attached a screenshot showing the current flat-list presentation.

The request is to retain the current flat list and add Tree View as an additional display option, similar to the view options in the VS Code Source Control sidebar.