Copilot CLI starts in wrong working directory

### Describe the bug

When `copilot` is launched, the agent worker process runs in a working directory that does **not** match the directory the user launched `copilot` from. Instead, the worker's CWD is set to the per-user VS Code install folder (`C:\Users\\AppData\Local\Programs\Microsoft VS Code`).

### Affected version

GitHub Copilot CLI 1.0.55-1

### Steps to reproduce the behavior

1. Open a fresh PowerShell 7 window via Windows Terminal
2. Confirm `pwd` shows `C:\Users\`.
3. Run `agency copilot --allow-all`.
4. Ask the agent: *"What is your current working directory?"* — or have it run any tool that reports CWD.

### Expected behavior

Agent CWD is `C:\Users\` (the directory `copilot` was launched from).
## Actual

Agent CWD is `C:\Users\\AppData\Local\Programs\Microsoft VS Code\`.

### Additional context

_No response_

Reproduce the issue from a fresh PowerShell 7 window with `agency copilot --allow-all`, then trace the CLI's agent worker startup and working-directory handling. Done means the worker reports the directory from which `copilot` was launched rather than the per-user VS Code installation folder.

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