Read stored manifests leniently and mark the defaults layer (hq ADR 0262 review)

A strict read of the stored catalogue fails every plan and send once a manifest uses a field an older
controller lacks; registration stays strict. A node named default lost its layer to the name check.
Judge the operator's keys by whole words, and scan a default under any key.

internal/catalogue/settings.go

@@ -30,6 +30,9 @@ type Layer struct {
 	// Where these came from, for saying which layer set a value.
 	From   string
 	Values map[string]any
+	// Default marks the layer a module's own defaults make (novox/hq ADR 0262). Marked rather than
+	// recognised by From, which is a node's name for a node's layer, and a node may be called anything.
+	Default bool
 }
 
 // ApplySettings produces a resource's final content from the module's own and the layers over it.
@@ -114,7 +117,7 @@ func overridden(base map[string]any, layers []Layer, what string) (map[string]an
 				values[key] = value
 			}
 		}
-		kept = append(kept, Layer{From: layer.From, Values: values})
+		kept = append(kept, Layer{From: layer.From, Values: values, Default: layer.Default})
 	}
 	merged, err := settle(base, kept, nil, what)
 	if err != nil {
@@ -151,7 +154,7 @@ func settle(base map[string]any, layers []Layer, protected map[string]bool, what
 	map[string]any, error) {
 	merged := deepCopy(base)
 	for _, layer := range layers {
-		if layer.From == DefaultLayer {
+		if layer.Default {
 			// A module's own defaults fill ${setting:<key>} only (novox/hq ADR 0262). A mergeable
 			// file's content already is its defaults, and a contribution or served fact declares its
 			// own; laid on here, a default would reach every mergeable file of its module (issue 168).