Regenerate a Mind's profile image

Queue AI generation of a new profile image for a Mind. The request returns as soon as the job is enqueued; poll GET /v1/minds/{mindId} until profileImageUrl is set or changes. The job is idempotent: when the Mind already has an image the endpoint returns enqueued: false with a skippedReason unless force: true, in which case the current image stays visible until a fresh portrait generated from the Mind's name, discipline, and system prompt replaces it. Pass personaContext to steer the image prompt without altering the stored system prompt. Callable by the owner or by a direct Mind member with the admin role; everyone else gets 403 Forbidden.