ai.newnal.illi.account.getAttestationNonce

Issue a server nonce (5 minutes) that a client binds into its attestation before calling account.requestPDNCreationGrant, account.parent.signIn, account.family.signIn or device.requestOnboardingCode. The nonce is an attestation session: the attestation bound to it may be presented again for the same client kind and subject until it expires; a failed verification ends the session. Devices put it in the Android key-attestation challenge of a key provisioned through Newnal's RKP; family apps pass it to Play Integrity or App Attest. No session required.