Say a module assigned and left out of its machine's composition as a condition (issue 380)

A push leaves out a module whose settings do not compose and sends the rest,
which is right, but only plan said so: nfs-server ran nowhere for days while
the operator believed it ran. The self-check now raises needs-operator for a
setting nobody gave, naming the setting and the command, and left-out for any
other cause; both warnings, cleared once the module composes or is unassigned.
status and node show list the same modules as assigned, not applied.

internal/catalogue/declaration.go

@@ -342,18 +342,38 @@ func (e *NotMadeError) Error() string {
 // compose. Empty when every module composes. The same judgement SetSettings makes before storing.
 func (r Resolution) LeftOut(settings SettingsBy, adopted bool) map[string]string {
 	out := map[string]string{}
+	for module, why := range r.LeftOutBecause(settings, adopted) {
+		out[module] = why.Error()
+	}
+	return out
+}
+
+// LeftOutBecause is LeftOut with each reason as the error it was, so a reader can tell a setting nobody
+// gave (an *UnsetSettingError) from any other cause and say it as the operator's to give (novox/hq issue
+// 380). An UnreadManifestError for a stored manifest this controller cannot read whole.
+func (r Resolution) LeftOutBecause(settings SettingsBy, adopted bool) map[string]error {
+	out := map[string]error{}
 	for _, m := range r.Modules {
 		if why := UnknownFieldReason(m); why != "" {
-			out[m.Module] = why
+			out[m.Module] = &UnreadManifestError{Module: m.Module, said: why}
 			continue
 		}
 		if err := JudgeSettings(m, settings[m.Module], adopted); err != nil {
-			out[m.Module] = err.Error()
+			out[m.Module] = err
 		}
 	}
 	return out
 }
 
+// UnreadManifestError is a module left out because its stored manifest has a key this controller does not know
+// (novox/hq ADR 0262): said once for the whole mesh, by the catalogue's own condition, not per machine.
+type UnreadManifestError struct {
+	Module string
+	said   string
+}
+
+func (e *UnreadManifestError) Error() string { return e.said }
+
 // Compose is Declaration with the owner of every resource said.
 func (r Resolution) Compose(with Rendering) (Composed, error) {
 	owner := map[string]string{}