Revoke all of an identity's sessions (admin)

Revokes all of an identity's sessions in the caller's Environment (server-to-server admin) by marking every active refresh token it holds there revoked, so the next refresh on any device returns 401 and the user must sign in again. Sessions in the identity's other Environments are left alone; the Console's account route is the one that signs a person out everywhere. In-flight access tokens remain valid until their short TTL lapses. Idempotent — revoking when no tokens are active is a no-op. Audits twice: identity.sessions.admin_revoked for the identity's own security log, and session.all_revoked, the subscribable webhook event, so a revoke made here reaches subscribers exactly as one made from the Console does. Returns 204 No Content; returns 404 when the identity has no membership in this Environment.