Prepare v0.4.0 release

[isty2e]

Summary

• bump the identedit package and lockfile version to 0.4.0
• update the README release example to v0.4.0
• upgrade all workflows from actions/checkout@v4 to actions/checkout@v7 to remove the Node.js 20 deprecation before release

Compatibility

This is release metadata and CI maintenance only. The canonical CLI, JSON protocol, edit semantics, and supported platform set are unchanged.

Validation

• go run github.com/rhysd/actionlint/cmd/actionlint@latest .github/workflows/*.yml
• cargo fmt --check
• cargo clippy --locked --all-targets -- -D warnings
• cargo test --locked (2,099 tests)
• cargo build --locked --release

[chatgpt-codex-connector]

💡 Codex Review

Here are some automated review suggestions for this pull request.

Reviewed commit: 581d54cd71

ℹ️ About Codex in GitHub

Your team has set up Codex to review pull requests in this repo. Reviews are triggered when you

• Open a pull request for review
• Mark a draft as ready
• Comment "@codex review".

If Codex has suggestions, it will comment; otherwise it will react with 👍.

Codex can also answer questions or update the PR. Try commenting "@codex address that feedback".

[chatgpt-codex-connector]

Pin checkout to a published major

The actions/checkout repository has no v7 ref, so every trigger of this workflow fails at the first checkout step with an unresolved action and never runs formatting, Clippy, tests, or builds. The same invalid ref is also used by release-binaries.yml and windows-apply-safety.yml, which prevents release assets and Windows safety tests from running; pin all four occurrences to a published checkout major such as v6.

Useful? React with 👍 / 👎.