KeyStatus represents the lifecycle state of an API key. - KEY_STATUS_UNSPECIFIED: Default zero value. Never returned by the server. Treated as ACTIVE for backward compatibility but should not be relied on. - KEY_STATUS_ACTIVE: The key is valid and can be used to authenticate. - KEY_STATUS_REVOKED: The key was revoked and can no longer authenticate. On the API key object, the revocation_reason field carries the cause (set via the admin and self-revocation flows). Verification responses do not include this status: a revoked key fails verification with error_code VERIFICATION_ERROR_REVOKED. - KEY_STATUS_EXPIRED: The key passed its expire_time. Verification fails with VERIFICATION_ERROR_EXPIRED. The transition is computed at read time and not persisted.