chore(release): bump version to 0.3.1

[Mossaka]

This pull request prepares for the 0.3.1 release by updating the version in Cargo.toml and Cargo.lock.

Changes

• Updated version in Cargo.toml to 0.3.1
• Updated Cargo.lock to reflect the version change

Next Steps

1. Review and merge this PR
2. After merge, create and push a new tag: git tag -s v0.3.1 -m "Release v0.3.1"
3. Push the tag: git push origin v0.3.1
4. The release workflow will automatically trigger and create the GitHub release
5. The update-package-manifests workflow will automatically create a PR to update Homebrew and WinGet manifests