CLI - Run fails when using private registry with error fetching bookworm-slim

I'm running Box CLI as follows

`boxlite --debug --config ~/.boxlite/config.json run internal.registry.com/base-images-docker/ubi-minimal:9.7-1773939694 ./boxlite-test.sh`

where `config.json` contains

```json
{
"image_registries": [
{
"host": "internal.registry.com",
"skip_verify": true,
"auth": {
"type": "basic",
"username": "username",
"password": "password"
}
}
]
}
```

It fails as follows to fetch the `bookworm-slim` image

```logs
2026-05-25T14:50:45.437598Z WARN boxlite::images::store: Layer download failed (attempt 3): error sending request for url (https://index.docker.io/v2/library/debian/blobs/sha256:068fedd6b0f109b8186d00d49327b6fc6747c428fd3c9a8739424ff5f38d7531)
2026-05-25T14:50:45.438145Z DEBUG boxlite::images::store: Failed to pull image candidate, trying next reference=docker.io/library/debian:bookworm-slim error=storage error: failed to pull layer sha256:068fedd6b0f109b8186d00d49327b6fc6747c428fd3c9a8739424ff5f38d7531: error sending request for url (https://index.docker.io/v2/library/debian/blobs/sha256:068fedd6b0f109b8186d00d49327b6fc6747c428fd3c9a8739424ff5f38d7531)
2026-05-25T14:50:45.438235Z ERROR boxlite::litebox::init::tasks: Task failed: storage error: Failed to pull image 'debian:bookworm-slim' after trying 1 registry:
- docker.io/library/debian:bookworm-slim: storage error: failed to pull layer sha256:068fedd6b0f109b8186d00d49327b6fc6747c428fd3c9a8739424ff5f38d7531: error sending request for url (https://index.docker.io/v2/library/debian/blobs/sha256:068fedd6b0f109b8186d00d49327b6fc6747c428fd3c9a8739424ff5f38d7531) box_id=hyLa6mtnN0TN task=guest_rootfs_init
2026-05-25T14:50:45.438319Z WARN boxlite::litebox::init::types: Box initialization failed, cleaning up box_id=hyLa6mtnN0TN reason=storage error: Failed to pull image 'debian:bookworm-slim' after trying 1 registry:
- docker.io/library/debian:bookworm-slim: storage error: failed to pull layer sha256:068fedd6b0f109b8186d00d49327b6fc6747c428fd3c9a8739424ff5f38d7531: error sending request for url (https://index.docker.io/v2/library/debian/blobs/sha256:068fedd6b0f109b8186d00d49327b6fc6747c428fd3c9a8739424ff5f38d7531)
2026-05-25T14:50:45.438331Z ERROR boxlite::litebox::init::types: Box failed. Diagnostic files preserved at:
/home/mark/.boxlite/boxes/hyLa6mtnN0TN
```

Ideally I'd be able to configure which image is used for `bookwork-slim` so it can be resolved via our internal registry docker mirror at `internal.registry.com/virtual-docker` instead of using `docker.io`