fix(create): report actual exit status when nsenter exits unsuccessfully

[mdryaan]

Description

handleNsenterRet in cmd/urunc/create.go wraps err with %w inthe branch that handles an unsuccessful nsenter exit. That branch isonly reachable when err == nil — the err != nil case is handled above it. The resulting error message always reads
"nsenter unsuccessful exit: <nil>", hiding the actual exit code.

Fixed by formatting the exit code from status.ExitCode() directly instead of wrapping err.

Related issues

• Fixes Report actual exit status when nsenter exits unsuccessfully #675

How was this tested?

Fix verified by code inspection — the branch is only reachable when err is nil, making the %w wrap provably wrong. All CI checks pass locally:

• golangci-lint run -v --timeout=5m — 0 issues
• go test ./pkg/unikontainers/... ./internal/metrics/... ./pkg/network/... — PASS
• make — builds successfully

LLM usage

N/A

Checklist

• I have read the contribution guide.
• The linter passes locally (make lint).
• The e2e tests of at least one tool pass locally (make test_ctr, make test_nerdctl, make test_docker, make test_crictl).
• If LLMs were used: I have read the llm policy.

[netlify]

✅ Deploy Preview for urunc canceled.

Name	Link
🔨 Latest commit	6b01d06
🔍 Latest deploy log	https://app.netlify.com/projects/urunc/deploys/6a06f9cd70396700081033bf

[cmainas]

Hello @mdryaan ,

you will need to add yourself in https://github.com/urunc-dev/urunc/blob/main/.github/contributors.yaml

[mdryaan]

Hello @mdryaan ,

you will need to add yourself in https://github.com/urunc-dev/urunc/blob/main/.github/contributors.yaml

@cmainas Done! Please take a look

[cmainas]

Hello @mdryaan ,

there are some conflicts that need to get resolved.

[mdryaan]

@cmainas Done

[cmainas]

Hello @mdryaan ,

please do not use merge commits. Simply rebase your changes over main

[mdryaan]

Hey @cmainas Done! Also after merging this please have a look on #674, I think its ready to merge