Rebuild a flat image into editable layers on a new canvas (metered; async job).

Creates a canvas sized to the image with the image placed as a full-page node, then starts the same hidden headless layerize job the in-app "Layerize" action runs: an agent reconstructs the image's background, objects, and text as separate editable nodes and merges the finished group back over the placed image. The response returns immediately with a task_id and the created canvas — poll GET /v1/media/layerize/{task_id} (about every retry_after_ms) until the status is terminal. The job typically takes a few minutes; the canvas shows the flat image until the merge lands.

Billing: metered as a normal agent run (model tokens plus per-call provider usage inside the job) against team credits — there is no fixed per-layerize price. The kickoff runs a credit precheck and returns the typed 402 when the balance refuses.