GHSA-hfvc-g4fc-pqhx

## Summary

The fix for GHSA-9h8m-3fm2-qjrq (CVE-2026-24051) changed the Darwin `ioreg` command to use an absolute path but left the BSD `kenv` command using a bare name, allowing the same PATH hijacking attack on BSD and Solaris platforms.

## Root Cause

`sdk/resource/host_id.go` line 42:

if result, err := r.execCommand("kenv", "-q", "smbios.system.uuid"); err == nil {

Compare with the fixed Darwin path at line 58:

result, err := r.execCommand("/usr/sbin/ioreg", "-rd1", "-c", "IOPlatformExpertDevice")

The `execCommand` helper at `sdk/resource/host_id_exec.go` uses `exec.Command(name, arg...)` which searches `$PATH` when the command name contains no path separator.

Affected platforms (per build tag in `host_id_bsd.go:4`): DragonFly BSD, FreeBSD, NetBSD, OpenBSD, Solaris.

The `kenv` path is reached when `/etc/hostid` does not exist (line 38-40), which is common on FreeBSD systems.

## Attack

1. Attacker has local access to a system running a Go application that imports `go.opentelemetry.io/otel/sdk` 2. Attacker places a malicious `kenv` binary earlier in `$PATH` 3. Application initializes OpenTelemetry resource detection at startup 4. `hostIDReaderBSD.read()` calls `exec.Command("kenv", ...)` which resolves to the malicious binary 5. Arbitrary code executes in the context of the application

Same attack vector and impact as CVE-2026-24051.

## Suggested Fix

Use the absolute path:

if result, err := r.execCommand("/bin/kenv", "-q", "smbios.system.uuid"); err == nil {

On FreeBSD, `kenv` is located at `/bin/kenv`.