Delete one of the caller's own desks and cascade-remove its data. Guard: body.confirm_name MUST equal the desk's CURRENT name (else 400) — a typed-name confirmation. 404 if the desk is not the caller's (cloak).

Cascade (db.delete_account_cascade, scoped to this account_id): orders, positions, deployment transitions, deployments, per-account key pairs, watchlists, alerts, then the desk row. Deleting the caller's last desk is allowed — there is no lower floor (the cap of 5 is the only hard limit).