Changes to “The keys of a node”

+ Guard the node key as carefully as a wallet key. Whoever holds it can claim the seat's stake to an account they control with ClaimNodeRegistration. The owner's own claim takes effect at once. Anyone else's claim is announced and executes 40,320 blocks (7 days) later, unless the owner removes the node first, so an owner who watches the chain has a week to react ([[leaving-the-registry]]). This is also the path for an owner who has lost access to the owner account: the claim then comes from another account, so it too executes 7 days later.