Say a part waiting for the operator as needs-operator and pass its gate; add secret families (issue 386, hq ADR 0283)

A module waiting for the operator's secret failed its first-node gate, held
every later walk and was said as 'nothing for you to do'. The node-engine's
new waiting state is checked against the manifest and the secrets given,
read by the gate as a wait for a person, and raised as needs-operator naming
the act. A secret family gives each part its own one-line secret, which the
mesh never makes, so the desk prompt can take each password.

cmd/mesh-controller/plan.go

@@ -664,7 +664,33 @@ func renderingFor(ctx context.Context, open *stores, node string,
 	needed := map[string]map[string]string{}
 	foreseen := map[string]map[string]bool{}
 	for _, m := range plan.Modules {
-		for name := range m.OwnSecrets {
+		// **A secret family is never made** (novox/hq ADR 0283): each member a person gave on this machine is
+		// placed, and one not given is nothing — the module says it waits for it.
+		for _, family := range m.OwnSecrets.Families() {
+			members, err := inv.GivenMembers(ctx, node, m.Module, family)
+			if err != nil {
+				return catalogue.Rendering{}, inventory.Node{}, err
+			}
+			for _, g := range members {
+				if _, fam, ok := m.OwnSecrets.Lookup(g.Name); !ok || fam != family {
+					continue // a longer family's member, or a name no longer of this family
+				}
+				if !g.Current {
+					if choosing == Allocating {
+						return catalogue.Rendering{}, inventory.Node{}, fmt.Errorf(
+							"%s on %s holds %q, which was given to the mesh rather than made by it, and %s has "+
+								"since generated a new sealing key. The mesh cannot make another; give it again",
+							m.Module, node, g.Name, node)
+					}
+					continue
+				}
+				if needed[m.Module] == nil {
+					needed[m.Module] = map[string]string{}
+				}
+				needed[m.Module][g.Name] = g.Sealed
+			}
+		}
+		for name := range m.OwnSecrets.Plain() {
 			// Minted on the send path and only read on every other. Making one is an insert, and
 			// a question that writes is a question that can block against the machine it is about.
 			var sealed string