Add shared internal UI toolkit for both readers

interaction/element.go

@@ -0,0 +1,39 @@
+// Copyright (c) 2026 Storm Dragon
+// Authors: Storm Dragon, Angus Kola
+// SPDX-License-Identifier: GPL-3.0-or-later
+
+package interaction
+
+import (
+	"bytes"
+	"encoding/json"
+	"errors"
+	"strings"
+)
+
+// UnmarshalJSON keeps a malformed secret flag from silently becoming an
+// ordinary entry (encoding/json otherwise accepts null for a boolean). The
+// wire decoder separately rejects duplicate keys and bounds nesting/framing.
+func (element *Element) UnmarshalJSON(data []byte) error {
+	type plain Element
+	var value plain
+	decoder := json.NewDecoder(bytes.NewReader(data))
+	decoder.DisallowUnknownFields()
+	if err := decoder.Decode(&value); err != nil {
+		return err
+	}
+	var fields map[string]json.RawMessage
+	if err := json.Unmarshal(data, &fields); err != nil {
+		return err
+	}
+	for name, raw := range fields {
+		if strings.EqualFold(name, "secret") {
+			flag := string(bytes.TrimSpace(raw))
+			if name != "secret" || flag != "true" && flag != "false" {
+				return errors.New("secret must be a boolean")
+			}
+		}
+	}
+	*element = Element(value)
+	return nil
+}