fix(mobile): birthday picker date order follows locale

mobile/lib/presentation/widgets/people/person_edit_birthday_modal.widget.dart

@@ -65,6 +65,7 @@ class _DriftPersonNameEditFormState extends ConsumerState<DriftPersonBirthdayEdi
         child: ClipRRect(
           borderRadius: const BorderRadius.all(Radius.circular(16.0)),
           child: ScrollDatePicker(
+            viewType: datePickerColumnOrder(DateFormat.yMd(context.locale.toLanguageTag()).pattern),
             options: DatePickerOptions(
               backgroundColor: context.colorScheme.surfaceContainerHigh,
               itemExtent: 50,
@@ -118,3 +119,18 @@ class _DriftPersonNameEditFormState extends ConsumerState<DriftPersonBirthdayEdi
     );
   }
 }
+
+List<DatePickerViewType>? datePickerColumnOrder(String? pattern) {
+  if (pattern == null) {
+    return null;
+  }
+  final positions = {
+    DatePickerViewType.year: pattern.indexOf('y'),
+    DatePickerViewType.month: pattern.indexOf('M'),
+    DatePickerViewType.day: pattern.indexOf('d'),
+  };
+  if (positions.values.any((position) => position < 0)) {
+    return null;
+  }
+  return positions.keys.toList()..sort((a, b) => positions[a]!.compareTo(positions[b]!));
+}

mobile/test/presentation/widgets/people/person_edit_birthday_modal_test.dart

@@ -0,0 +1,65 @@
+import 'package:flutter_test/flutter_test.dart';
+import 'package:immich_mobile/presentation/widgets/people/person_edit_birthday_modal.widget.dart';
+import 'package:intl/date_symbol_data_local.dart';
+import 'package:intl/intl.dart';
+import 'package:scroll_date_picker/scroll_date_picker.dart';
+
+void main() {
+  group('datePickerColumnOrder', () {
+    test('month first (en_US)', () {
+      expect(
+        datePickerColumnOrder('M/d/y'),
+        orderedEquals([DatePickerViewType.month, DatePickerViewType.day, DatePickerViewType.year]),
+      );
+    });
+
+    test('day first (pl)', () {
+      expect(
+        datePickerColumnOrder('dd.MM.y'),
+        orderedEquals([DatePickerViewType.day, DatePickerViewType.month, DatePickerViewType.year]),
+      );
+    });
+
+    test('year first (ko)', () {
+      expect(
+        datePickerColumnOrder('y. M. d.'),
+        orderedEquals([DatePickerViewType.year, DatePickerViewType.month, DatePickerViewType.day]),
+      );
+    });
+
+    test('null pattern falls back to package default', () {
+      expect(datePickerColumnOrder(null), isNull);
+    });
+
+    test('missing field falls back to package default', () {
+      expect(datePickerColumnOrder('M/y'), isNull);
+    });
+  });
+
+  group('datePickerColumnOrder with real locale patterns', () {
+    setUpAll(() async {
+      await initializeDateFormatting();
+    });
+
+    test('en uses month/day/year', () {
+      expect(
+        datePickerColumnOrder(DateFormat.yMd('en').pattern),
+        orderedEquals([DatePickerViewType.month, DatePickerViewType.day, DatePickerViewType.year]),
+      );
+    });
+
+    test('pl uses day/month/year', () {
+      expect(
+        datePickerColumnOrder(DateFormat.yMd('pl').pattern),
+        orderedEquals([DatePickerViewType.day, DatePickerViewType.month, DatePickerViewType.year]),
+      );
+    });
+
+    test('ko uses year/month/day', () {
+      expect(
+        datePickerColumnOrder(DateFormat.yMd('ko').pattern),
+        orderedEquals([DatePickerViewType.year, DatePickerViewType.month, DatePickerViewType.day]),
+      );
+    });
+  });
+}