Use of bun instead of npm/yarn

### Before opening, please confirm:

- [X] I have checked to see if my question is addressed in the [FAQ](https://github.com/aws-amplify/amplify-hosting/blob/master/FAQ.md).
- [X] I have [searched for duplicate or closed issues](https://github.com/aws-amplify/amplify-hosting/issues?q=is%3Aissue+).
- [X] I have read the guide for [submitting bug reports](https://github.com/aws-amplify/amplify-hosting/blob/master/CONTRIBUTING.md).
- [X] I have done my best to include a minimal, self-contained set of instructions for consistently reproducing the issue.
- [X] I have removed any sensitive information from my code snippets and submission.

### App Id

dz7vabxjlpaqd

### AWS Region

ap-south-1

### Amplify Hosting feature

Git providers

### Frontend framework

React

### Next.js version

NA

### Next.js router

N/A

### Describe the bug

Since the bun is the fastest instead of npm/yarn to create the build, I want to use the bun. Can anyone suggest me the Build Image for the same?

### Expected behavior

NA

### Reproduction steps

NA

### Build Settings

_No response_

### Log output

```
# Put your logs below this line

```

### Additional information

_No response_

Start with FAQ.md and the repository's documented build settings to determine how build images and package managers are configured. Compare the requested Bun workflow with the existing npm/yarn guidance and any relevant hosting configuration entry points. Done means the supported approach, required configuration, or lack of Bun support is clearly documented.

Written by the indexing model from the issue text.