persist history options

app/lib/data/database/converters/date_time_range.dart

@@ -0,0 +1,27 @@
+import 'package:flutter/material.dart';
+import 'package:json_annotation/json_annotation.dart';
+
+class DateTimeRangeConverter
+    implements JsonConverter<DateTimeRange?, Map<String, dynamic>?> {
+  const DateTimeRangeConverter();
+
+  @override
+  DateTimeRange? fromJson(Map<String, dynamic>? json) {
+    if (json == null) return null;
+
+    return DateTimeRange(
+      start: DateTime.parse(json['start'] as String),
+      end: DateTime.parse(json['end'] as String),
+    );
+  }
+
+  @override
+  Map<String, dynamic>? toJson(DateTimeRange? dateTimeRange) {
+    if (dateTimeRange == null) return null;
+
+    return {
+      'start': dateTimeRange.start.toIso8601String(),
+      'end': dateTimeRange.end.toIso8601String(),
+    };
+  }
+}