A node carries its operator account (name + home; migration 0036, Node.Account,
SetAccount, 'node account' CLI). The account and its home are offered as
machine facts ${machine:account} / ${machine:account-home}, and machineInto
now resolves placeholders in a resource's path and owner (not just content), so
a module writes into a person's home naming what it cannot know. A RosterFile
gains Home: the file is placed under the account's home and chowned to it, its
template sees each node's Account, and a machine with no account gets none —
this is how the ssh Host blocks for every node reach a person's ~/.ssh. Roster
carries per-node accounts (Rendering.Accounts). Tested, including ssh-client
composed end-to-end. Not deployed.
