ci: update actions, golangci-lint, and test against oldest (go.mod), oldstable, and stable

[thaJeztah]

• fix linting
• ci: update actions and golangci-lint
• ci: apply zizmor fixes, ping actions by sha
• ci: remove custom working-directories and GOPATH
• ci: test against oldest (go.mod), oldstable, and stable Go versions

[Copilot]

Pull request overview

This PR updates the project’s CI and linting posture while making small code/test tweaks to satisfy the updated static analysis configuration (notably gosec) and improve documentation.

Changes:

• Updates golangci-lint configuration to v2 format, enabling additional linters (e.g., gosec, govet) and extending lint timeout.
• Hardens GitHub Actions workflow (pinned action SHAs, explicit permissions) and expands test matrix to cover minimum (go.mod), oldstable, and stable Go versions.
• Adds/adjusts inline suppression comments and minor code/test cleanups to align with the new linting expectations.

Reviewed changes

Copilot reviewed 8 out of 8 changed files in this pull request and generated 1 comment.

Show a summary per file

File	Description
socket.go	Adds gosec suppression comments and makes cleanup calls explicitly best-effort.
runc.go	Adds package-level documentation for the public runc package.
runc_test.go	Refines the parallel/race-oriented test to better synchronize goroutines and asserts Version parsing doesn’t error on empty output.
monitor.go	Marks an unused parameter explicitly unused to satisfy linters.
command_other.go	Adds gosec suppression for intentional exec.CommandContext usage.
command_linux.go	Adds gosec suppression for intentional exec.CommandContext usage (Linux variant).
.golangci.yml	Migrates to golangci-lint v2 config format; enables gosec/govet and introduces formatters.
.github/workflows/ci.yml	Pins actions by SHA, scopes permissions, updates linter invocation, and expands Go test matrix.

---

💡 Add a code-review agent skill or configure MCP servers for context-aware, tailored reviews. Learn more in the docs.

[thaJeztah]

You're hallucinating; goimports and gofmpt are a formatter in Golangci-lint v2; both formatters and linters will fail CI if not done correctly.