Revoke a connection: status revoked, encrypted token row deleted, audited.

Idempotent, so a client that lost the response may safely repeat it; the ciphertext is never resurrected. An unknown or foreign connection is not_found, identical to one that never existed. Do not retry a not_found. Requires the explicitly minted bernayser:write scope; bernayser:read permits safe projections and bernayser:write permits mutations. This BERNAYSER operation is quota-neutral. While dark it returns not_found, and a valid key without the required scope receives scope_missing. Fix a non-retryable request or credential before retrying; for rate_limited or service_unavailable, wait for retry_after_sec and retry once.