[macOS + nerdbox] `nerdctl run` fails with `not implemented`

On macOS with nerdbox, `nerdctl run` fails with `not implemented`

```console
$ nerdctl --debug run --rm --snapshotter erofs --runtime io.containerd.nerdbox.v1 --platform=linux alpine
DEBU[0000] verifying process skipped
FATA[0000] not implemented
```

The image is pulled with ctr, as `nerdctl pull` still does not work on macOS either:
- https://github.com/containerd/nerdctl/issues/4570

Version:

- containerd v2.2.0-rc.0
- nerdctl 2ba655af
- nerdbox containerd/nerdbox@5f30298b164bc203b2bb05d6deac340be906fd60
- Will be public soon https://github.com/containerd/project/issues/154
- macOS 26.0.1

- - -
Call stack:
https://github.com/containerd/nerdctl/blob/804a8cd0c38bf11188d35265f09c7e5a4e00a8ef/pkg/cmd/container/create.go#L253-L256
https://github.com/containerd/nerdctl/blob/804a8cd0c38bf11188d35265f09c7e5a4e00a8ef/pkg/cmd/container/run_mount.go#L218
https://github.com/containerd/containerd/blob/a6fa1d7fe569cbd08a1effbe15c8a97205360f6a/core/mount/mount.go#L50
https://github.com/containerd/containerd/blob/a6fa1d7fe569cbd08a1effbe15c8a97205360f6a/core/mount/mount_darwin.go#L22-L24