[All Platforms][CLI&UX] host probe records no host OS distribution or version, so an unqualified OS release is never warned about before install

## Description

`nemoclaw host probe` records no host operating-system distribution or version, so an unsupported or untested OS is never surfaced to the user before install or onboarding proceeds.

The JSON report contains **36 observations**. It records the platform family (`host.os.platform = linux`), the architecture, and whether the host is WSL, but there is no observation carrying the distribution name or its version. The only observation ids containing a version are `host.docker.cgroup_version`, `host.gpu.driver_version` and `gateway.version_drift`, none of which describe the host OS. No finding of any severity is emitted for the OS version either.

The practical consequence: a user on an OS the product has not qualified gets no early warning from the readiness surface, and the first signal is a failure later in install or onboarding. A generic Linux or WSL host is accepted regardless of the distribution release it is running.

**Platform scope:** Reproduced on DGX Station (Ubuntu 24.04.4 LTS, aarch64) and on a WSL2 host (Ubuntu 24.04.4 LTS, x86_64). Both report the same 36 observations with no OS version.
**Regression:** Unknown — earlier versions not tested for this.

## Environment

```text
Device: DGX Station (aarch64) and a WSL2 x86_64 host
OS: Ubuntu 24.04.4 LTS on both
Architecture: aarch64 and x86_64
Node.js: v22.23.2
npm: 10.9.8
Docker: 29.2.1 (Station), Docker Desktop 29.5.3 (WSL2)
OpenShell CLI: 0.0.106
NemoClaw: v0.0.119
```

## Steps to Reproduce

1. On any supported Linux or WSL2 host, run `nemoclaw host probe`.
2. Run `nemoclaw host probe --json`.
3. Inspect the observation ids for one describing the host OS distribution or its version.

## Expected Result

The readiness report records the host operating system distribution and version, and emits a warning when the host runs a release the product has not qualified, so the user learns this before install or onboarding proceeds.

## Actual Result

```text
36 observations are returned. The ones carrying a version are:
host.docker.cgroup_version
host.gpu.driver_version
gateway.version_drift

None describes the host OS. The OS-related observations are limited to:
host.os.platform = linux
host.os.architecture = arm64 (or x64)
host.os.wsl = true or false

No finding mentions the operating system release.
```

## Logs

```text
DGX Station, Ubuntu 24.04.4 LTS aarch64:
observation count 36; version-bearing ids: host.docker.cgroup_version, host.gpu.driver_version, gateway.version_drift

WSL2, Ubuntu 24.04.4 LTS x86_64:
observation count 36; version-bearing ids: host.docker.cgroup_version, host.gpu.driver_version, gateway.version_drift
```

Start by running `nemoclaw host probe` and `nemoclaw host probe --json` on the Linux and WSL2 environments described in the issue, then trace the host-probe entry point that produces the 36 observations. Done means the report includes the host distribution and version, and emits a warning for an unqualified OS release before installation or onboarding.

Written by the indexing model from the issue text.