✨ Enrich user profile settings

lib/services/timezone/web.dart

@@ -0,0 +1,21 @@
+import 'package:flutter_timezone/flutter_timezone.dart';
+import 'package:timezone/browser.dart' as tz;
+
+Future<void> initializeTzdb() async {
+  await tz.initializeTimeZone();
+}
+
+(Duration offset, DateTime now) getTzInfo(String name) {
+  final location = tz.getLocation(name);
+  final now = tz.TZDateTime.now(location);
+  final offset = now.timeZoneOffset;
+  return (offset, now);
+}
+
+Future<String> getMachineTz() async {
+  return await FlutterTimezone.getLocalTimezone();
+}
+
+List<String> getAvailableTz() {
+  return tz.timeZoneDatabase.locations.keys.toList();
+}