`.github` folder in a project is not used in the worktree

### Feature summary

Use the `.github` (and private) folders for projects as well

### What problem are you trying to solve?

The session does not take the `.github` or `github-private` folders into account when creating a worktree of a mutli repo project. I created a helpful canvas in a session which I can find in the `.github` repo, yet when I create a new session I cannot use the canvas.

### Proposed solution

Also use the `.github` or `github-private` folders in the worktree.

### Workflow impact

Especially used for multi-repo projects, misses config and functionality right now, including org level Copilot instructions.

### Installation context

_No response_

### Additional context

Local folder setup:

Copilot App:

Worktree:

Empieza rastreando cómo una sesión con múltiples repositorios crea su worktree y selecciona las carpetas de los repositorios; comprueba cómo se gestionan .github y github-private. Se considera completado cuando esas carpetas se incluyen en el worktree, de modo que los canvas, la configuración y las instrucciones de Copilot a nivel de organización estén disponibles en una sesión nueva.

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