v0.23.1

Features

• Core — A new editor.placeholder runtime API (get/set) lets consumers read and change the empty-paragraph placeholder on a live editor, mirroring the existing width API. Updates apply to existing blocks and to blocks created afterwards.
• React — <BlokEditor> now accepts a reactive placeholder prop (backed by the new core API) that updates the editor in place without recreating it, and forwards all standard <div> attributes — id, aria-*, data-*, and the like — to the editor container.