Cubic-bezier easing conversion utility (experimental)

Editor assessment

feat(animation) says a cubic-bezier easing conversion utility is added and marks it experimental, with the pull request in the header and a valid resolution footer. The scope and feature type fit, and the subject is imperative and unterminated. The experimental tag usefully flags maturity, though no body explains the utility's purpose or API. Clear and correctly classified, it is publishable with a modest context omission.