Add feedback service, reminder diagnostics and smooth week transitions

mobile/test/widgets/week_swipe_test.dart

@@ -6,6 +6,7 @@ import 'package:hepan_everyday/domain/app_snapshot.dart';
 import 'package:hepan_everyday/domain/app_settings.dart';
 import 'package:hepan_everyday/domain/schedule_engine.dart';
 import 'package:hepan_everyday/features/timetable/timetable_page.dart';
+import 'package:hepan_everyday/widgets/directional_week_transition.dart';
 
 import '../support/fakes.dart';
 
@@ -51,6 +52,45 @@ Future<void> _open(WidgetTester tester, AppController controller) async {
 
 void main() {
   setUpAll(tzdata.initializeTimeZones);
+  testWidgets(
+    'week arrows animate the grid and current week reverses direction',
+    (tester) async {
+      await _open(tester, _controller());
+      await tester.tap(find.byIcon(Icons.chevron_right_rounded));
+      await tester.pump();
+      await tester.pump(const Duration(milliseconds: 100));
+      expect(find.byType(DirectionalWeekTransition), findsOneWidget);
+      expect(find.text('第1周课程'), findsOneWidget);
+      expect(find.text('第2周课程'), findsOneWidget);
+      expect(
+        tester
+            .widget<FractionalTranslation>(
+              find.byKey(const Key('week-transition-incoming')),
+            )
+            .translation
+            .dx,
+        greaterThan(0),
+      );
+      await tester.pumpAndSettle();
+      expect(find.text('第1周课程'), findsNothing);
+      await tester.tap(find.text('本周'));
+      await tester.pump();
+      await tester.pump(const Duration(milliseconds: 100));
+      expect(
+        tester
+            .widget<FractionalTranslation>(
+              find.byKey(const Key('week-transition-incoming')),
+            )
+            .translation
+            .dx,
+        lessThan(0),
+      );
+      await tester.pumpAndSettle();
+      expect(find.text('第 1 周'), findsOneWidget);
+      expect(find.text('第2周课程'), findsNothing);
+      expect(find.text('周日'), findsOneWidget);
+    },
+  );
   testWidgets(
     'horizontal course swipe changes week and course taps still open',
     (tester) async {