The merge commit took only the staged index; these reconciliation edits sat
unstaged in the working tree. Integrate the template mechanism with #79's
region write (hq 128): RosterFile gains Shared, FactsInto sets into:block for
a shared fact, /etc/hosts becomes the region form (no floor) and node-names is
marked shared. Without this the merge would have regressed /etc/hosts back to
a whole-file write, replacing the operator's own lines.
A roster fact used to be a name from a closed list, each formatted in Go
here — node-names as a hosts file, node-zones as a resolver's zones. Every
new consumer (ssh's known_hosts, an authorized_keys) meant another formatter
in the control plane, in the consumer's own configuration language.
Now a fact is a path and a Go template over the roster view (this node, the
suffix, and every served name vs the machines). The mesh owns the data; the
module owns the format. /etc/hosts is a template on the network module;
dnsmasq's zones move to dnsmasq. The controller renders and reads neither.
WireGuard stays a computed generator: the overlay is the substrate delivery
rides on, and its config is topology, not a roster projection.
Output is byte-for-byte unchanged, pinned by the hosts golden tests and the
resolver tests that compose the real dnsmasq manifest.