kiro-cli chat interactive mode silently exits with IAM Identity Center (SSO) auth in v2.0.0

### 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

Linux 5.15.0-171-generic - Ubuntu 22.04.5 LTS

### Expected behaviour

kiro-cli chat should start the interactive TUI session after successful IAM Identity Center (SSO) login, as it did in previous versions.

### Actual behaviour

kiro-cli chat exits immediately with no output. Exit code is 1.

Running with verbose logging (kiro-cli chat -vv) shows:

2026-04-16T21:44:58.827515Z INFO q_cli::cli: 542: no social token found
2026-04-16T21:44:58.827565Z INFO q_cli::cli: 560: no idp token found

The interactive mode does not recognize IAM Identity Center (SSO) tokens. However, non-interactive mode works perfectly with the same auth:

kiro-cli chat --no-interactive "hello" → responds correctly, uses 0.03 credits

This is a regression — interactive chat worked with IAM Identity Center auth prior to the v2.0.0 update.

### Steps to reproduce

1. SSH into a Linux bastion host (Ubuntu 22.04)
2. kiro-cli logout
3. kiro-cli login → select IAM Identity Center → complete browser auth → "Logged in successfully"
4. kiro-cli chat → exits immediately, no output
5. echo $? → returns 1
6. kiro-cli chat --no-interactive "hello" → works fine

### Environment

```yaml

[q-details]
version = "2.0.0"
hash = "0026b0505ef7bc2b10780c7bdb57813e5d949747"
date = "2026-04-13T09:03:52.798806Z (4d ago)"
variant = "minimal"

[system-info]
chip = "QEMU Virtual CPU version 2.5+"
total-cores = 16
memory = "15.61 GB"

[system-info.os.linux]
kernel_version = "5.15.0-171-generic"
id = "ubuntu"
name = "Ubuntu"
pretty_name = "Ubuntu 22.04.5 LTS"
version_id = "22.04"
version = "22.04.5 LTS (Jammy Jellyfish)"

[environment]
cwd = "/home/USER/2026"
cli-path = "/home/USER/2026"
os = "Linux"
shell-path = "/usr/bin/bash"
shell-version = "5.1.16"
install-method = "unknown"
in-ssh = true

[env-vars]
PATH = "/home/USER/.local/bin:/home/USER/bin:/home/USER/bin:/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/games:/usr/local/games:/snap/bin"
SHELL = "/bin/bash"
TERM = "xterm-256color"
XDG_SESSION_TYPE = "tty"
```

Beginne beim q_cli::cli-Pfad für ausführliche Protokollierung und reproduziere den Fehler bei der Authentifizierung mit IAM Identity Center unter Verwendung der aufgeführten kiro-cli login- und chat-Befehle. Vergleiche den interaktiven Modus mit --no-interactive und überprüfe, dass der interaktive Chat nach der SSO-Anmeldung erfolgreich startet, ohne mit Code 1 zu beendet zu werden.

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