AWS Toolkit generates JSON credentials incompatible with AWS CLI

## Problem

AWS Toolkit generates credentials in **JSON format**, but the AWS CLI expects **INI-style text credentials**. As a result, credentials produced by the Toolkit cannot be used directly by the AWS CLI, causing errors when running CLI commands.

## Steps to reproduce the issue

1. Install AWS Toolkit in Visual Studio Code.
2. Configure a profile using the Toolkit.
3. Generate credentials for that profile.
4. Attempt to use the same profile with the AWS CLI, e.g., `aws s3 ls`.
5. Observe that the CLI fails to read the JSON credentials.

## Expected behavior

Credentials generated by AWS Toolkit should either:
- Be compatible with AWS CLI directly, or
- Provide an option to export in **CLI-compatible INI format**.

The issue names no source files or tests; start by locating the Toolkit credential-generation entry point and comparing its JSON output with the AWS CLI's expected INI format. Reproduce the flow with an AWS profile and `aws s3 ls`; done means generated credentials are directly CLI-compatible or an explicit INI export option is available.

Written by the indexing model from the issue text.