v0.5.0

Minor Changes

• ba7f231: Add rpc.markFinal(...signals) to promise clients a signal will never change
  again. Final signals serialize as {"@S": id, "v": value, "f": 1}: the client
  still gets a Signal, but observing it sends no @W and the server never
  subscribes to it. A signal that becomes final while clients watch it is
  announced with a debounced N:@S:id,null,"seal" update, which forwarding
  relays. The server drops its subscriptions immediately, while seal updates are
  batched for one second. Existing append, merge, and splice modes remain strings.