ai.newnal.illi.family.credentialEnvelope

A parent's credentials (Newnal ID handle and password, scoped app passwords, parent 1's Private Phone key) sealed by the ILLI device to the root admin's custody public key (crypto_box_seal: ephemeral X25519 + HKDF + AES-256-GCM). Written by the device in the parent's repo; only the root admin can open it. Deleted by the device once a custodyReceipt is seen.