Review summary: #4315

Change reviewed

This PR backports the lint fix from #4314 to the v3 branch ahead of the golangci-lint v2.13 update in #4299. It makes two contained changes:

• .buildkite/pipeline.yml now includes .buildkite/Dockerfile-lint in the lint step's if_changed paths, so changing the image that supplies golangci-lint actually schedules the lint job.
• internal/socket/server_test.go replaces the deprecated http.Transport.Dial callback with DialContext, forwarding the request context through net.Dialer.DialContext while continuing to connect to the same Unix socket.

Evidence and verification

I read the complete two-file diff and the full changed files. I also inspected:

• .buildkite/docker-compose.yml, which confirms that the lint service is built from .buildkite/Dockerfile-lint.
• .buildkite/steps/check-code-committed.sh, which confirms that this pipeline step runs golangci-lint.
• internal/socket/client.go, whose production Unix-socket transport already uses the same context-aware dialing pattern.
• Other Unix-socket HTTP test clients in the repository for surrounding conventions.
• The original merged PR #4314 and the pending v3 dependency update #4299 to verify the backport's intent and ordering.

git diff --check passed, and the checked-out commit matched the PR head (67dc9f87fd12d9f4e4c7c4cf239bdfc41a89a411). No Linear issue identifier was present in the branch name, PR title, or PR description.

I could not run go test ./internal/socket, go tool gofumpt, or golangci-lint in this review environment because the Go toolchain and golangci-lint binary were not installed. The PR reports successful local runs of the full Go test suite, the targeted socket tests, formatting, and golangci-lint v2.13.2. At review time, the Buildkite agent build #14227 was still pending; the category-label and Socket security checks had passed.

Findings and verdict

No correctness, security, compatibility, or pipeline-configuration issues were found. The new pipeline path names the Dockerfile actually consumed by the lint service, and the test update removes the deprecated transport hook without changing its intended Unix-socket behavior while adding cancellation support.

The review was submitted as APPROVED with no inline findings.

Trigger source: automatic.