**Title:** Copilot App cannot authenticate HTTP GitLab repositories when crea...

**Title:** Copilot App cannot authenticate HTTP GitLab repositories when creating a worktree

I'm encountering an authentication issue when using GitHub Copilot App with an HTTP-based GitLab repository.

### Environment

* GitHub Copilot App (standalone application)
* macOS
* Git repository hosted on GitLab
* Remote URL uses HTTP (not SSH)

Example:

```text
http://git.x'x'x'x.com/java/xxxxx.git
```

### Problem

When Copilot App creates a new worktree, it appears to execute a `git fetch` before creating the worktree. That fetch fails with the following error:

```text
fatal: could not read Username for 'http://git.cqweaver.com': terminal prompts disabled
```

As a result, the worktree creation fails.

### What makes this confusing

Running the exact same operation from my terminal works without any issue:

```bash
git fetch
```

It completes successfully without prompting for credentials, which indicates that my Git credentials are already configured correctly and are available to Git in my normal shell environment.

### Expected behavior

Copilot App should be able to authenticate using the same Git credentials that are available to the system Git (for example, via the configured Git credential helper or macOS Keychain), rather than failing because terminal prompts are disabled.

### Actual behavior

Copilot App cannot authenticate the HTTP GitLab repository during the background `git fetch`, even though the repository works normally from the terminal on the same machine.

### Additional information

This appears to be specific to the Git environment used by Copilot App when creating worktrees. Since `git fetch` succeeds in the terminal but fails only when invoked by Copilot App, it seems that the application may not be inheriting or using the system's Git credential configuration correctly.

If this is a known limitation, it would be helpful if the documentation mentioned it. Otherwise, I believe Copilot App should support the same authentication mechanism as the system Git for HTTP-based Git repositories.

---
| Field | Value |
| --- | --- |
| App version | 1.0.19 |
| OS | macOS 13.7.6 |
| Theme | GitHub |
| Path | / |
| Tenure | Week 6 |

Start by reproducing worktree creation with the HTTP GitLab repository on macOS and compare the Git environment used by the Copilot App with the terminal environment. Trace the background git fetch and verify that configured credentials are used without terminal prompts; done means the worktree is created successfully with the existing system Git credentials.

索引モデルが issue の本文から書いたものです。