feat(ui,train): a pull far enough to refresh ticks, lightly, as the navigation does

AppRefreshIndicator ticks (selectionClick, as a choice on the floating bar
or the rail) once the pull commits: as it snaps back to refresh, or as it
refreshes at once, whichever comes first, and not for a pull let go too
early. Train's list of days pulled to read the band used Flutter's own
RefreshIndicator, the older spinner; it takes the app's now, and the tick
with it.

Whats-New: Pulling a list down to refresh ticks lightly.
Whats-New-De: Eine Liste zum Aktualisieren herunterziehen gibt ein leichtes Tippen.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Signed-off-by: Tizian 「ティツィアーン」 <raisondetredev@pm.me>

apps/train/halkyon_train_flutter/lib/src/feature/day/widget/days_list.dart

@@ -55,7 +55,7 @@ class const DaysList({super.key}) extends StatelessWidget {
         if (!state.holdsLoop) {
           return list;
         }
-        return RefreshIndicator(
+        return AppRefreshIndicator(
           onRefresh: () => context.read<DaysCubit>().readBand(),
           child: list,
         );

packages/halkyon_ui/lib/src/widget/app_loading_indicator.dart

@@ -1,4 +1,7 @@
+import 'dart:async';
+
 import 'package:expressive_loading_indicator/expressive_loading_indicator.dart';
+import 'package:flutter/services.dart';
 import 'package:material_ui/material_ui.dart';
 
 /// The app's spinner for anything still loading: Material 3 Expressive's
@@ -40,7 +43,8 @@ class const ButtonLoadingIndicator({super.key}) extends StatelessWidget {
 /// meanwhile, as Material 3 Expressive's pull to refresh has it: in a small
 /// round container that comes down with the pull and stays while it
 /// refreshes. Flutter's own [RefreshIndicator] draws the older spinner, so
-/// it only does the pulling here (its `noSpinner` kind).
+/// it only does the pulling here (its `noSpinner` kind). A pull far enough
+/// to refresh ticks, lightly, as a choice on the navigation bar does.
 class const AppRefreshIndicator({
   required final RefreshCallback onRefresh,
   required final Widget child,
@@ -110,6 +114,15 @@ class _AppRefreshIndicatorState() extends State<AppRefreshIndicator> {
           child: RefreshIndicator.noSpinner(
             onRefresh: widget.onRefresh,
             onStatusChange: (status) => setState(() {
+              // Snapping back to refresh, or refreshing at once: let go
+              // far enough, whichever comes first.
+              const committed = {
+                RefreshIndicatorStatus.snap,
+                RefreshIndicatorStatus.refresh,
+              };
+              if (committed.contains(status) && !committed.contains(_status)) {
+                unawaited(HapticFeedback.selectionClick());
+              }
               _status = status;
               if (status == RefreshIndicatorStatus.done ||
                   status == RefreshIndicatorStatus.canceled) {

packages/halkyon_ui/test/widget/app_refresh_indicator_test.dart

@@ -1,6 +1,7 @@
 import 'dart:async';
 
 import 'package:expressive_loading_indicator/expressive_loading_indicator.dart';
+import 'package:flutter/services.dart';
 import 'package:flutter_test/flutter_test.dart';
 import 'package:halkyon_ui/halkyon_ui.dart';
 import 'package:material_ui/material_ui.dart';
@@ -40,4 +41,50 @@ void main() {
     await tester.pumpAndSettle();
     expect(find.byType(ExpressiveLoadingIndicator), findsNothing);
   });
+
+  group('a light tick', () {
+    Future<List<Object?>> pulled(WidgetTester tester, double by) async {
+      final haptics = <Object?>[];
+      tester.binding.defaultBinaryMessenger.setMockMethodCallHandler(
+        SystemChannels.platform,
+        (call) async {
+          if (call.method == 'HapticFeedback.vibrate') {
+            haptics.add(call.arguments);
+          }
+          return null;
+        },
+      );
+      addTearDown(
+        () => tester.binding.defaultBinaryMessenger.setMockMethodCallHandler(
+          SystemChannels.platform,
+          null,
+        ),
+      );
+      await tester.pumpWidget(
+        MaterialApp(
+          theme: appTheme(Brightness.light),
+          home: Scaffold(
+            body: AppRefreshIndicator(
+              onRefresh: () async {},
+              child: ListView(
+                physics: const AlwaysScrollableScrollPhysics(),
+                children: const [Text('Japanese')],
+              ),
+            ),
+          ),
+        ),
+      );
+      await tester.fling(find.text('Japanese'), Offset(0, by), 1000);
+      await tester.pumpAndSettle();
+      return haptics;
+    }
+
+    testWidgets('as a pull far enough refreshes, once', (tester) async {
+      expect(await pulled(tester, 400), ['HapticFeedbackType.selectionClick']);
+    });
+
+    testWidgets('but none for a pull let go too early', (tester) async {
+      expect(await pulled(tester, 20), isEmpty);
+    });
+  });
 }