Emitted when a credential has an expiry_at but the provider supplies no
refresh()
handler. The session will terminate at expiry with no fallback.
Implementors who want long-lived sessions must provide a refresh() handler or
mint tokens with the sat:refresh scope (Client Bound SAT path). Subscribe via
client.warnings$.
Discriminant identifying this warning.
The SDK subsystem that emitted the warning.
Human-readable description of the warning.
Token expiry timestamp (epoch milliseconds).