Agent roles

V1 does not require named council voices. It needs clear agent producer roles.

Role	Responsibility
Frame producer	Submits media and metadata through the Agent API.
Review assistant	Adds review notes or flags risky metadata in the workbench.
Media processor	Tracks derivative and video processing status.
Generation service	V2 server-side producer that creates media and metadata before submission.

Roles can be represented as metadata on submissions and events.