feat(boss): Boss creates nests and assigns registry crows (#43)

nests.go

@@ -44,9 +44,22 @@ func invalid(format string, a ...any) error {
 
 // NestStore holds the nests and saves the ones people create to disk.
 type NestStore struct {
-	path string
-	mu   sync.Mutex
-	made []Nest // created nests, in creation order; the default nest is not stored
+	path      string
+	mu        sync.Mutex
+	made      []Nest                 // created nests, in creation order; the default nest is not stored
+	allowCrow func(name string) bool // extra member names beyond the roster (spun crows)
+}
+
+// AllowCrows extends the names that may be nest members beyond the persona
+// roster: the server wires it to the spun-crow registry so the Boss can
+// staff a nest with registry crows (#43). It is set once at wiring time,
+// before anything is served; Create stays the only mutation.
+func (s *NestStore) AllowCrows(ok func(name string) bool) { s.allowCrow = ok }
+
+// memberKnown reports whether a name may join a nest: a working persona crow
+// (the roster excludes the service roles) or an allowed extra name.
+func (s *NestStore) memberKnown(name string) bool {
+	return slices.Contains(roster, name) || (s.allowCrow != nil && s.allowCrow(name))
 }
 
 func LoadNests(path string) (*NestStore, error) {
@@ -104,7 +117,7 @@ func (s *NestStore) Create(name string, crows []string) (Nest, error) {
 		return Nest{}, invalid("A nest has 1 to %d crows.", len(roster))
 	}
 	for i, c := range crows {
-		if !slices.Contains(roster, c) {
+		if !s.memberKnown(c) {
 			return Nest{}, invalid("%q is not in the flock. Choose from %s.", c, strings.Join(roster, ", "))
 		}
 		if slices.Contains(crows[:i], c) {