Add shared internal UI toolkit for both readers

internalui/message/messages.go

@@ -0,0 +1,27 @@
+// Copyright (c) 2026 Storm Dragon
+// SPDX-License-Identifier: GPL-3.0-or-later
+
+package message
+
+import (
+	"strconv"
+	"strings"
+)
+
+// Messages belongs to one session. Translate must be safe for the host's
+// calling context; a nil function selects the built-in English messages.
+type Messages struct{ Translate func(string) string }
+
+func (m Messages) T(message string) string {
+	if m.Translate != nil {
+		return m.Translate(message)
+	}
+	return message
+}
+func (m Messages) Format(message string, fields ...string) string {
+	replacements := []string{"{{", "{", "}}", "}"}
+	for index, value := range fields {
+		replacements = append(replacements, "{"+strconv.Itoa(index)+"}", value)
+	}
+	return strings.NewReplacer(replacements...).Replace(m.T(message))
+}