Prepare v0.2.5 release

[JamesLinYJ]

Summary

• bump the package and lockfile version from 0.2.4 to 0.2.5
• allow the release workflow to react to version-file changes merged into main
• derive the release tag from Cargo metadata, create the missing lightweight tag with the job-scoped GitHub token, and continue validation/build/publish in the same run
• preserve existing tag-push and manual-dispatch release paths
• skip cleanly when the Cargo version already has a tag

Why

Merging PR #15 correctly ran CI but did not create a release because release.yml only listened for pre-existing v* tags. This change makes an intentional version bump on main the release boundary while retaining the existing tag/version validation and artifact verification.

Validation

• git diff --check
• Cargo.toml and Cargo.lock both resolve to 0.2.5
• YAML parse succeeded
• actionlint 1.7.12 passed for .github/workflows/release.yml
• PR CI remains the authoritative Windows fmt/check/Clippy/test/build gate