Code signing for gh-aw binaries

When installing or running the `gh-aw` GitHub CLI extension on Windows, Microsoft Defender immediately blocks/quarantines `gh-aw.exe`.

This prevents using commands such as:

```powershell
gh aw compile
````

### Detection

Microsoft Defender detection:

```text
Trojan:Win32/Wacatac.B!ml
```

The alert appears immediately after installing the extension.

### Affected file

```text
C:\Users\\AppData\Local\GitHub CLI\extensions\gh-aw\gh-aw.exe
```

### Steps to reproduce

```powershell
gh extension remove github/gh-aw
gh extension install github/gh-aw
gh aw compile
```

### Actual result

Windows Defender blocks the extension binary.

Example error:

```text
failed to run extension: fork/exec C:\Users\\AppData\Local\GitHub CLI\extensions\gh-aw\gh-aw.exe:
Operation did not complete successfully because the file contains a virus or potentially unwanted software.
```

### Expected result

The extension installs and runs without being blocked by Microsoft Defender.

### Environment

```text
OS: Windows 11
GitHub CLI version: 2.93.0
gh-aw version: 0.76.1
Install command: gh extension install github/gh-aw
Defender detection: Trojan:Win32/Wacatac.B!ml
```