kiro-cli not working after update

### 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 26.6.1 (25G76)

### Expected behaviour

Kiro works normally

### Actual behaviour

I'm currently using the version 2.5.0, after updating kiro to 2.18.1, I cannot select model nor chat with LLM. The /model option becomes not available.

### Steps to reproduce

_No response_

### Environment

```yaml

[q-details]
version = "2.18.1"
hash = "74b78bb5a369788e393b06654b2b213d937a41d2"
date = "2026-08-13T23:20:56.707604Z (5d ago)"
variant = "full"

[system-info]
os = "macOS 26.6.1 (25G76)"
chip = "Apple M1 Pro"
total-cores = 10
memory = "16.00 GB"

[environment]
cwd = "/Users/USER/Documents/SDS Efficiency/Clinical Trial Simulator"
cli-path = "/Users/USER/Documents/SDS Efficiency/Clinical Trial Simulator"
os = "Mac"
shell-path = "/bin/zsh"
shell-version = "5.9"
terminal = "Positron"
install-method = "brew"

[env-vars]
PATH = "/opt/homebrew/bin:/Users/USER/.pyenv/shims:/Users/USER/.pyenv/bin:/Users/USER/.local/bin:/Users/USER/.local/bin:/opt/homebrew/bin:/opt/homebrew/sbin:/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:/pkg/env/global/bin:/Applications/Privileges.app/Contents/Resources:/Users/USER/Library/TinyTeX/bin/universal-darwin:/Users/USER/Library/Application Support/Positron/User/globalStorage/github.copilot-chat/debugCommand:/Users/USER/Library/Application Support/Positron/User/globalStorage/github.copilot-chat/copilotCli:/Applications/Positron.app/Contents/Resources/app/extensions/positron-python/python_files/deactivate/zsh:/Users/USER/.pyenv/versions/3.11.15/bin:/Users/USER/.pyenv/bin:/Users/USER/.local/bin:/Users/USER/.positron/extensions/ms-python.debugpy-2026.6.0-darwin-arm64/bundled/scripts/noConfigScripts"
QTERM_SESSION_ID = "1d38f683f08244ecae748b05c72935b4"
Q_SET_PARENT_CHECK = "1"
Q_TERM = "2.18.1"
SHELL = "/bin/zsh"
TERM = "xterm-256color"
ZDOTDIR = "/Users/USER"
__CFBundleIdentifier = "co.posit.positron"
```

Reproduce the report with Kiro 2.18.1 on macOS 26.6.1, comparing the previously working 2.5.0 behavior. Run q doctor and q restart in the affected terminal, then verify whether model selection, chat, and the /model option become available; there are no reproduction steps, files, or tests named in the issue.

Written by the indexing model from the issue text.