Option to open right sidebar as separate window

### Feature summary

Sidebars as separate windows

### What problem are you trying to solve?

Feature request:
Sometimes it would be very useful, if the right (panels) sidebar could be opened in a **new window**. This would also give some extensive canvases more realestate. All tabs (like Changes, Terminal, Insights, ...) should remain in this new window, same as now in the sidebar.

---
| Field | Value |
| --- | --- |
| App version | 1.1.7 |
| OS | macOS 15.7.9 |
| Theme | GitHub |
| Path | /chat |
| Tenure | Week 7 |

### Proposed solution

A new settings option, that toggles between "sidebar in main App window" and "sidebar as separate window"

If set to separate window, all tabs of current right sidebar appear in a new window of the running Copilot App

### Workflow impact

- Canvases have more realestate
- multi-display environments profit

### Installation context

_No response_

### Additional context

_No response_

No se nombran archivos, pruebas ni puntos de entrada. Empieza por localizar la implementación de la barra lateral derecha y de la configuración, y después delimita el comportamiento de la ventana independiente para todas las pestañas de la barra lateral enumeradas. Se considera terminado cuando una configuración puede cambiar entre la barra lateral de la ventana principal y una ventana independiente, conservando esas pestañas y dando más espacio a los lienzos.

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