Unable to Open CLI Chat from Copilot Session Pane (Right Side) Error: Failed to open chat session: Illegal argument: character must be non-negative

### Describe the bug

I am unable to open a CLI chat from the Copilot session panel on the right side of VS Code.
Whenever I try, the following error is shown:

Failed to open chat session: Illegal argument: character must be non-negative
This blocks me from starting a CLI chat session from the Copilot UI.

### Affected version

GitHub Copilot CLI 1.0.61.

### Steps to reproduce the behavior

1. Open VS Code.
2. Open Copilot chat/session panel on the right side.
3. Attempt to start or open a CLI chat session.
4. Observe the error popup/message.

### Expected behavior

A new CLI chat session should open successfully.

### Additional context

The operation fails with:
Failed to open chat session: Illegal argument: character must be non-negative

similar to this one: https://github.com/microsoft/vscode/issues/319726

Comienza reproduciendo el fallo en VS Code con GitHub Copilot CLI 1.0.61 desde el panel de sesión de Copilot del lado derecho y, después, compara el comportamiento con el issue vinculado de VS Code. Rastrea el punto de entrada que abre la sesión de chat de CLI e identifica dónde se produce el argumento de carácter no negativo; se considera terminado cuando un nuevo chat de CLI se abre correctamente sin el error.

Escrito por el modelo de indexación a partir del texto del issue.