data(readiness): read vast-ai's spec for the key the agent manages

[auscaster]

Vast.ai's GPU instance listing now names the key operations in the OpenAPI document it already cites:

• POST /api/v0/auth/apikeys ("create api-key") and DELETE /api/v0/auth/apikeys/{id} ("delete api key").
• Both take the same bearer key as the job, so an agent rotates its own key (north star §5.6, Sustain).