Misleading error message suggests non-existent /model command

### 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 15.5.0 (24F74)

### Expected behaviour

Error message should provide valid troubleshooting steps or commands that actually exist in the CLI.

### Actual behaviour

When the model is temporarily unavailable, Amazon Q CLI shows an error message suggesting to use '/model' to select a different model, but this command doesn't exist and causes user confusion.

```
[chat-transcript]
I see you're trying to use a `/model` command, but this doesn't appear to be a valid command for Amazon Q CLI.

Here are the available commands and options for Amazon Q:

**Main commands:**
- `q c

> fix /model eevertime I am getting this errors

I understand you're getting errors with `/model` every time you try to use it. However, `/model` is not a valid command in Amazon Q CLI chat sessions.

To help you fix this issue, I need to understand what you're trying to accomplish. Are you:

1. **Trying to switch between different AI models?** - This isn't available as a chat command in Amazon Q CLI
2. **Getting this error in a different application?** - Please specify which application or tool you're using
3. **Expecting this to work based on other AI chat interfaces?** - Amazon Q CLI has its own specific command set

**Valid commands in Amazon Q CLI chat:**
- `/quit` - Exit the chat
- Regular questions and requests (no slash commands needed)

**To get help with Amazon Q CLI:**
\```bash
q --help
\```

Could you share:
- The exact error message you're seeing?
- What you expected `/model` to do?
- Whether this is happening in Amazon Q CLI or another tool?

This will help me provide the right solution for your specific situation.
[Tool uses: none]

> Amazon Q is having trouble responding right now: >
0: The model you've selected is temporarily unavailable. Please use '/model' to select a different model and try again.>
Request ID: 31e33a7a-e853-49fa-add4-808a5de05c37>
>
0: >
>
Location:>
crates/chat-cli/src/cli/chat/mod.rs:723>
>
Backtrace omitted. Run with RUST_BACKTRACE=1 environment variable to display it.>
Run with RUST_BACKTRACE=full to include source snippets.

I see the issue now! You're getting an error message that suggests using `/model` to select a different model, but this appears to be a bug in the Amazon Q CLI error message itself.

The `/model` command doesn't actually exist in Amazon Q CLI, which is why you're having trouble with it. This looks like an internal error where the model I'm running on is temporarily unavailable.

Here are some steps to resolve this:

## Immediate Solutions:

1. **Restart the chat session:**
\```bash
/quit
\```
Then start a new session:
\```bash
q chat
\```

2. **Check your AWS configuration:**
\```bash
aws configure list
q --help
\```

3. **Try with a different AWS region (if applicable):**
\```bash
export AWS_DEFAULT_REGION=us-east-1
q chat
\```

## If the problem persists:

1. **Update Amazon Q CLI:**
\```bash
# If installed via npm
npm update -g @aws/amazon-q-developer-cli

# Or check for updates through your package manager
\```

2. **Check service status:**
The error suggests a temporary model unavailability, which could be a service-side issue.

## Report the Bug:

This error message is misleading since `/model` isn't a valid command. Would you like me to help you report this issue to the Amazon Q team?
[Tool uses: report_issue]

(...truncated)
```

### Steps to reproduce

1. Encounter model unavailability error 2. Try to use suggested '/model' command 3. Command fails because it doesn't exist

### Environment

```yaml

[q-details]
version = "1.12.2"
hash = "b9100eb751546269f095585705a0e7fc3ea55419"
date = "2025-06-30T22:40:01.105251Z (2d ago)"

[system-info]
os = "macOS 15.5.0 (24F74)"
chip = "Apple M2 Pro"
total-cores = 12
memory = "16.00 GB"

[environment]
cwd = "/Users/USER/cirrus"
cli-path = "/Users/USER/cirrus"
install-method = "brew"

[env-vars]
PATH = "/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:/Users/USER/.local/bin:/Users/USER/Library/Application Support/Code/User/globalStorage/github.copilot-chat/debugCommand"
QTERM_SESSION_ID = "5777c7a187d54f53b52b3b6478ab3462"
Q_SET_PARENT_CHECK = "1"
Q_TERM = "1.12.2"
SHELL = "/opt/homebrew/bin/zsh"
TERM = "xterm-256color"
ZDOTDIR = "/Users/USER"
__CFBundleIdentifier = "com.microsoft.VSCode"

[chat-settings]

[chat-trusted_tools]
execute_bash=true
fs_write=true

[chat-failed_request_ids]
none

[chat-context]
current_profile=default
profiles=
default

global_context=
.amazonq/rules/**/*.md
README.md
AmazonQ.md

profile_context=none

files=none
```