bash 5

### Checks

- [x] I have searched [github.com/aws/amazon-q-developer-cli/issues](https://github.com/aws/amazon-q-developer-cli/issues?q=) and there are no duplicates of my issue
- [x] I have run `q doctor` in the affected terminal session
- [x] I have run `q restart` and replicated the issue again

### Operating system

macOS 26.5.1 (25F80)

### Expected behaviour

Using Bash 3.2.57 may cause issues, it is recommended to either update to bash >=5 or switch to zsh.
- Install Bash 5 with Brew: brew install bash && bash
- Change shell default to ZSH: chsh -s /bin/zsh && zsh
✔ Everything looks good!

Kiro CLI still not working? Run kiro-cli issue to let us know

### Actual behaviour

Using Bash 3.2.57 may cause issues, it is recommended to either update to bash >=5 or switch to zsh.
- Install Bash 5 with Brew: brew install bash && bash
- Change shell default to ZSH: chsh -s /bin/zsh && zsh
✔ Everything looks good!

Kiro CLI still not working? Run kiro-cli issue to let us know

### Steps to reproduce

_No response_

### Environment

```yaml

[q-details]
version = "2.8.1"
hash = "43ca6648d9e72889f9b499548df52a230d216456"
date = "2026-06-17T23:47:37.987102Z (2d ago)"
variant = "full"

[system-info]
os = "macOS 26.5.1 (25F80)"
chip = "Apple M3"
total-cores = 8
memory = "8.00 GB"

[environment]
cwd = "/Users/USER"
cli-path = "/Users/USER"
os = "Mac"
shell-path = "/bin/zsh"
shell-version = "5.9"
terminal = "macOS"
install-method = "unknown"

[env-vars]
PATH = "/Users/USER/.antigravity-ide/antigravity-ide/bin:/Applications/ServBay/script/alias:/Applications/ServBay/bin:/Applications/ServBay/sbin:/Applications/ServBay/script:/Applications/ServBay/package/node/current/bin:/Users/USER/.antigravity/antigravity/bin:/Users/USER/.antigravity/antigravity/bin:/Users/USER/.antigravity/antigravity/bin:/Users/USER/.antigravity/antigravity/bin:/opt/homebrew/opt/php@8.2/sbin:/opt/homebrew/opt/php@8.2/bin:/opt/homebrew/opt/php@8.1/sbin:/opt/homebrew/opt/php@8.1/bin:/opt/homebrew/sbin:/opt/homebrew/bin:/usr/local/bin:/System/Cryptexes/App/usr/bin:/usr/bin:/bin:/usr/sbin:/sbin:/var/run/com.apple.security.cryptexd/codex.system/bootstrap/usr/local/bin:/var/run/com.apple.security.cryptexd/codex.system/bootstrap/usr/bin:/var/run/com.apple.security.cryptexd/codex.system/bootstrap/usr/appleinternal/bin:/Users/USER/.composer/vendor/bin:/Users/USER/.local/bin"
QTERM_SESSION_ID = "a95acaa2bd7641079053d705103e4c36"
Q_SET_PARENT_CHECK = "1"
Q_TERM = "2.8.1"
SHELL = "/bin/zsh"
TERM = "xterm-256color"
__CFBundleIdentifier = "com.apple.Terminal"
```

Start by reproducing the report with `q doctor` in the reported macOS terminal and compare the detected shell with the displayed Bash warning. Done means the diagnostic accurately reflects the active shell and gives appropriate guidance without reporting a misleading result.

Written by the indexing model from the issue text.