Record whether a node is adopted and which modules were taken on it (hq ADR 0100)

cmd/mesh-controller/main.go

@@ -126,7 +126,7 @@ func usage() {
 	fmt.Fprint(os.Stderr, `mesh-controller — the control plane
 
   migrate                        bring each context's schema up to date
-  node add <name>                create a node record
+  node add <name> [--adopted]    create a node record; --adopted: the machine is in use
   node list                      the nodes this mesh knows about
   node show <name>               what one machine reported it can do, and why
   node public-domain <name>      the domain it composes its routed names under
@@ -134,6 +134,7 @@ func usage() {
   node public-domain <name> --clear   ...it faces the outside no longer
   token issue --node <name>      a one-time right to join, for an existing record
   token issue --new <name>       create the record and issue for it
+  token issue ... --adopted      ...for a machine in use, which joins adopted
   identity show                  this control plane's signing key
   broker show                    where the broker is, and what to expect there
   serve                          consume what nodes say, and answer