docs: clarify enterprise settings required for Copilot App to work

### Short summary

_No response_

### Affected version or release

v1.0.10

### Installation context

mac-os

### What happened?

Attempting to use the app against a data residency domain in AU (ghe.com).

I'm getting "retry loading models" after authorisation has completed successfully and starting the first session.

I'm unclear which enterprise settings need to be enabled

- GitHub CLI is one,
- CLI remote control? Or will it fail gracefully with a subset of features available if this isn't set?
- Presumably not 'preview features' anymore now the app is GA?

Same local setup is fine with a personal account.

### Steps to reproduce

_No response_

### Expected behavior

_No response_

### Additional context

_No response_

首先找到有关在 ghe.com 等企业数据驻留域中使用 Copilot App 的文档，然后查看授权和模型加载要求。明确是否必须启用 GitHub CLI、CLI remote control 或 preview 功能，并记录设置不可用时的预期行为。

由索引模型根据 Issue 内容生成。