When the CLI displays a tree view of text, the colors are all not the same.

### Describe the bug

Describe the bug
When display results in a tree in the CLI, the last nodes leave color is incorrect.

● General-purpose(claude-opus-4.6) 🏗️ Neo: Create migration issues
│ Read history.md
│ │ .squad\agents\neo\history.md
│ └ L1:5 (4 lines read)
└ Edit history.md +27
└ .squad\agents\neo\history.md

In the screenshot, you will see that from "General-purpose" to just above edit, it is bright white, and the edit node is gray or off-white

Steps to reproduce the behavior
You just need to get a response that shows a tree.

### Affected version

GitHub Copilot CLI 1.0.34

### Steps to reproduce the behavior

You just need to get a response that shows a tree.

### Expected behavior

The colors should be the same

### Additional context

_No response_

Start by reproducing a tree response in the CLI using the affected version, then trace the tree rendering and color handling from the CLI entry point. Done means the final nodes use the same color as the surrounding tree text and the behavior is covered by an appropriate test if the existing test structure permits it.

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