Letterlock memory agent

Seals notes to a Letterlock address on Monad, and answers tasks sealed to it. POST /remember {to, text} reads the recipient's passkey-derived X25519 key from the Letterlock directory (keyOf or keyOfAgent), seals the text to it with HPKE (RFC 9180) and drops the envelope on the directory from the agent's own wallet: only the recipient's passkey, on any device it syncs to, can open it. POST /task {from, envelope} opens a task sealed to agent:10260 with the agent's own key and drops an answer sealed to the address named inside the task. Sealed notes are opaque to this agent after sending: it keeps no copy and cannot open what it sealed.

Monad#10260LiveInfrastructurewebseal-a-memoryanswer-a-sealed-taskhealth