chore(orch): log the process state

[jakubno]

Log the process state even if in another state than D

[cursor]

PR Summary

Medium Risk
Touches Firecracker process shutdown/kill behavior and adds a new gopsutil-based status lookup; mistakes here could cause missed/extra SIGKILLs or reduced observability during sandbox teardown. Change is small but in a reliability-critical path.

Overview
Replaces the ps-based process state probe with a gopsutil-based getProcessStatus helper and updates Stop() to capture and log the Firecracker process status right before issuing SIGKILL after the 10s SIGTERM grace period, while also handling the "process already exited" case via process.ErrorProcessNotRunning.

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[arkamar]

I would guess that getProcessState() will most commonly return error because process was killed and reaped and it no longer exists (kill syscall returns when signal was delivered). Therefore I would expect state equal to "" in most cases. I would suggest to change it to something like this:

state, err := getProcessState(ctx, p.cmd.Process.Pid)
if err != nil {
   // undecided what exactly to do here, because `err` is mostly a good sign here original `Warn()` is a bit misleading.
} else {
   logger.L().Info(ctx, "sent SIGKILL to fc process", logger.WithSandboxID(p.files.SandboxID), zap.String("state", state))
}

[arkamar]

I don't like getProcessState() function. Calling extra process for one letter from /proc/<pid>/stat file is overkill. gopsutils has StatusWithContext() but it maps Linux letters to strings https://github.com/shirou/gopsutil/blob/c2a1624b9f3ed0b38ad67134b93397142ed67a23/process/process.go#L609

[arkamar]

It is probably ok to leave it as it is, but I dropped the comment for the record. The chance, that the process will exit literally right after the timer event should be close to zero.

[arkamar]

Should we return here? The kill will fail as well, because the process is not running anymore.