Q CLI not working

### 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 15.7.1 (24G231)

### Expected behaviour

Amazon Q is having trouble responding right now:
0: Failed to send the request: unhandled error (AccessDeniedException)
1: unhandled error (AccessDeniedException)
2: service error
3: unhandled error (AccessDeniedException)
4: Error { code: "AccessDeniedException", message: "The bearer token included in the request is invalid.", aws_request_id: "eee153cf-f554-489a-8b11-9b491044d43e" }

Location:
crates/chat-cli/src/cli/chat/mod.rs:1024

Backtrace omitted. Run with RUST_BACKTRACE=1 environment variable to display it.
Run with RUST_BACKTRACE=full to include source snippets.

### Actual behaviour

Amazon Q is having trouble responding right now:
0: Failed to send the request: unhandled error (AccessDeniedException)
1: unhandled error (AccessDeniedException)
2: service error
3: unhandled error (AccessDeniedException)
4: Error { code: "AccessDeniedException", message: "The bearer token included in the request is invalid.", aws_request_id: "eee153cf-f554-489a-8b11-9b491044d43e" }

Location:
crates/chat-cli/src/cli/chat/mod.rs:1024

Backtrace omitted. Run with RUST_BACKTRACE=1 environment variable to display it.
Run with RUST_BACKTRACE=full to include source snippets.

### Steps to reproduce

_No response_

### Environment

```yaml

[q-details]
version = "1.18.1"
hash = "a46a9baa79edc62d59b078f95d46760d0c68d6c4"
date = "2025-10-13T23:05:39.763695Z (8d ago)"
variant = "full"

[system-info]
os = "macOS 15.7.1 (24G231)"
chip = "Apple M4 Pro"
total-cores = 14
memory = "48.00 GB"

[environment]
cwd = "/Users/USER"
cli-path = "/Users/USER"
os = "Mac"
shell-path = "/bin/zsh"
shell-version = "5.9"
terminal = "iTerm 2"
install-method = "brew"

[env-vars]
PATH = "/opt/homebrew/opt/openjdk/bin:/opt/homebrew/opt/python@3.12/libexec/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:/Applications/iTerm.app/Contents/Resources/utilities:/Users/USER/.local/bin"
QTERM_SESSION_ID = "fbdd3dbe4fbc49f98576ba8e0f4c99d5"
Q_SET_PARENT_CHECK = "1"
Q_TERM = "1.18.1"
SHELL = "/bin/zsh"
TERM = "xterm-256color"
__CFBundleIdentifier = "com.googlecode.iterm2"
```

Inizia eseguendo `q doctor` e `q restart` nella sessione del terminale interessata, quindi ispeziona la posizione dell’errore in `crates/chat-cli/src/cli/chat/mod.rs:1024`. Traccia il modo in cui vengono gestiti il bearer token non valido e `AccessDeniedException`, e utilizza l’ambiente macOS segnalato per riprodurre il problema. Il completamento deve includere una risoluzione verificata del problema della richiesta CLI e una copertura di test adeguata.

Scritto dal modello di indicizzazione a partire dal testo della issue.