Let a provider serve its consumers its own composed names (hq ADR 0346, issue 624)

The forge writes every package tarball at its public name, and its
consumers had no source for that name but a second copy kept by hand,
though the mesh composes it for the forge's route. A served value may now
name the provider's own names; a name its machine does not compose leaves
the key out, and the plan says so.

internal/catalogue/resolve.go

@@ -111,6 +111,9 @@ type Provider struct {
 	// (novox/hq to-be 23), and the pair is what tells the holder of a seat apart from another module
 	// providing the same thing (ADR 0110).
 	Module string
+	// LeftOut says each served key left out of Serves because that node composes no name it asks
+	// for (novox/hq ADR 0346 §3): said under each consumer's need.
+	LeftOut []string
 }
 
 // Held is a claim somebody already has, used for the scopes wider than one node.
@@ -230,6 +233,9 @@ type Needed struct {
 	// state, not a consumer missing its key. Set by the plan, which is the only layer that knows a
 	// licence's manager; empty for every consumer.
 	Manager bool
+	// LeftOut says each served key the provider left out, because its machine composes no name the
+	// value asks for (novox/hq ADR 0346 §3).
+	LeftOut []string
 	// Module is the providing module on From, empty for a need answered by a record or by nothing
 	// that serves it. A provider is a (node, module) pair (novox/hq to-be 23), and a binding to data
 	// is a binding to the pair (ADR 0232).
@@ -582,7 +588,7 @@ func Resolve(catalogue map[string]Manifest, assigned []string, node Node, world
 					bound = pm.IdentityBoundOf(want)
 				}
 				needs = append(needs, Needed{Name: want, From: p.Node, At: p.At, Module: p.Module,
-					Serves: p.Serves, For: because[want], SharedOwn: shared, Identity: bound})
+					Serves: p.Serves, For: because[want], SharedOwn: shared, Identity: bound, LeftOut: p.LeftOut})
 			}
 			switch {
 			case world.Unchecked: