Run the session's next turns on another profile

Moves an active, paused or stopped session onto profile_id, a profile this host's catalog allows with the session's repository, or, for a session created without one, a profile whose repository_mode is optional or none. It takes effect at the next turn that starts: a turn running now finishes on the profile it started with, and its worker then leaves so the next one claims the new profile and restores the session's checkpoint, conversation included. The session then runs the new profile's default model, whatever model it was created with. Earlier turns keep their record and cost; each turn's attempts[].profile_id says what it ran on.

The new profile must run the same runtime kind and version, since the next worker restores checkpoints that runtime took, and must be billed the same way (billing: none or not), since the session's cost limit stays as it is. A session created from an agent release runs the release's profile and answers 409 RELEASE_PROFILE_MISMATCH. The change settles in the request: the receipt is succeeded with result {previous_profile_id, profile_id}, and a status event on the stream carries both. Naming the profile the session already runs changes nothing and still answers succeeded.

Scope: sessions:control (API key or cookie session). Idempotency-Key: required.