Fill a preference's ${setting:} from its manifest default (hq ADR 0262)

Without a default, a running module could never gain a setting: the file asking for it
failed to compose until set, and the key was refused as stray until a file asked for it.
Defaults sit under the mesh's and the node's settings, never merge into a JSON file, are
refused for the operator's own values, and settings shows each value's source.

internal/catalogue/declaration.go

@@ -907,7 +907,7 @@ func (r Resolution) compose(with Rendering, owner map[string]string,
 			// **An operator's value, from the assignment** (novox/hq ADR 0112, ADR 0155): what a
 			// definition may not carry because it is true of one installation only. Filled from
 			// the same layers a mergeable file takes, and refused when no layer set it.
-			if err := settingInto(copied, with.Settings[m.Module], m.Module); err != nil {
+			if err := settingInto(copied, WithDefaults(m, with.Settings[m.Module]), m.Module); err != nil {
 				return nil, err
 			}
 			// **Placed before anything reads a path.** A pathless directory receives the path
@@ -1495,7 +1495,7 @@ func (r Resolution) composed(m Manifest, to string, raw map[string]any, layers [
 	// Overridden, not merged: a setting changes a key the contribution declares and adds none.
 	// The provider reads the contribution as a contract, and a setting made for one of this
 	// module's files is no part of it (novox/hq 04-ISSUES/173).
-	values, err := overridden(raw, layers, what)
+	values, err := overridden(raw, WithDefaults(m, layers), what)
 	if err != nil {
 		return nil, fmt.Errorf("%s: %w", what, err)
 	}
@@ -1926,7 +1926,7 @@ func (r Resolution) servedOnThisMachine(provision string, with Rendering) (map[s
 			// one, so keep looking rather than concluding from the first.
 			continue
 		}
-		settled, err := Settle(serves, with.Settings[m.Module])
+		settled, err := Settle(serves, WithDefaults(m, with.Settings[m.Module]))
 		if err != nil {
 			return nil, false, fmt.Errorf("%s serving %s: %w", m.Module, provision, err)
 		}