kiro-cli not updating since version 2.19.0

### 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 7.0.0-1011-aws - Ubuntu 26.04 LTS

### Expected behaviour

kiro-cli must update as soon there is one available.

### Actual behaviour

kiro-cli ceased to update. Below is the error that occurs in the end of update process:

$ kiro-cli update
████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████ 100/100error: failed to unpack `/tmp/.tmpCrmUAf/kirocli/bin/kiro-cli-chat`

If this is unexpected, try running kiro-cli doctor and then try again.

### Steps to reproduce

$ kiro-cli update
████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████ 100/100error: failed to unpack `/tmp/.tmpCrmUAf/kirocli/bin/kiro-cli-chat`

If this is unexpected, try running kiro-cli doctor and then try again.

$ kiro-cli doctor

✔ Everything looks good!

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

### Environment

```yaml

[q-details]
version = "2.19.0"
hash = "60eb656b3201c6e0a5b800c3b9dde677e0e33396"
date = "2026-08-19T22:22:48.411638Z (9d ago)"
variant = "minimal"

[system-info]
chip = "Intel(R) Xeon(R) CPU E5-2686 v4 @ 2.30GHz"
total-cores = 2
memory = "3.82 GB"

[system-info.os.linux]
kernel_version = "7.0.0-1011-aws"
id = "ubuntu"
name = "Ubuntu"
pretty_name = "Ubuntu 26.04 LTS"
version_id = "26.04"
version = "26.04 LTS (Resolute Raccoon)"

[environment]
cwd = "/home/USER/Documents/prj002_altcoin_screener"
cli-path = "/home/USER/Documents/prj002_altcoin_screener"
os = "Linux"
shell-path = "/usr/bin/bash"
shell-version = "5.3.9"
install-method = "unknown"
in-ssh = true

[env-vars]
PATH = "/home/USER/.npm-global/bin:/home/USER/.local/bin:/home/USER/.npm-global/bin:/home/USER/anaconda3/bin:/home/USER/anaconda3/condabin:/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/games:/usr/local/games:/snap/bin:/home/USER/.local/bin"
QTERM_SESSION_ID = "ce601a6bbc6644df8eb5478e639e8362"
Q_SET_PARENT_CHECK = "1"
Q_TERM = "2.19.0"
SHELL = "/bin/bash"
TERM = "xterm-256color"
XDG_SESSION_TYPE = "tty"
```

Beginne damit, `kiro-cli update` in der gemeldeten Linux-Umgebung zu reproduzieren, und untersuche den Updater-Pfad, der das Entpacken von `kiro-cli-chat` behandelt. Vergleiche den Update-Fehler mit der erfolgreichen Ausgabe von `kiro-cli doctor` und vorhandenen Updater-Tests, falls verfügbar. Als erledigt gilt die Aufgabe, wenn ein Update von Version 2.19.0 ohne den Entpackfehler abgeschlossen wird und die installierte CLI die neue Version erreicht.

Vom Indexierungsmodell aus dem Issue-Text verfasst.