Leave out a module whose stored manifest has an unknown field, and raise it (hq ADR 0262 review)

A key dropped silently ran a module without what its manifest says, and a key inside a block still
failed the whole catalogue. Judge a key by what it is about, and narrow the listing to one machine.

internal/catalogue/data.go

@@ -159,7 +159,7 @@ func (b *DataBackup) UnmarshalJSON(raw []byte) error {
 	dec := json.NewDecoder(bytes.NewReader(raw))
 	dec.DisallowUnknownFields()
 	if err := dec.Decode(&full); err != nil {
-		return fmt.Errorf("a data item's backup is \"copy\", \"none\" or {dump, into}: %w", err)
+		return fmt.Errorf("a data item's backup is \"copy\", \"none\" or {dump, into}: %w", typedUnknown(err))
 	}
 	*b = DataBackup{Dump: full.Dump, Into: full.Into}
 	return nil