Stage 5: History, the shared daily Streak and Reminders

- Streak computed from all complete Sessions: Grace Hour (00:00-01:00
  counts for yesterday unless it is done), a Freeze per 7 Streak Days
  (max 2) spent automatically on a missed day (ADR 0006)
- Top bar flame (grey until today is done) opening a panel with current
  and longest Streak, Freezes and a month calendar; 'Day N of your
  streak' on a fresh summary
- History per Mode grouped by day, reopening each summary
- Two adjustable Reminders (19:00, 22:30) scheduled 14 days ahead with
  flutter_local_notifications, none on a done day; permission asked
  after the first complete Session or from Settings
- Settings: Reminders, the Player chime, exercise credits

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

test/streak/reminders_test.dart

@@ -0,0 +1,69 @@
+import 'package:flutter_test/flutter_test.dart';
+import 'package:zenxercise/src/streak/reminders.dart';
+import 'package:zenxercise/src/streak/streak.dart';
+
+void main() {
+  const evening = Reminder(enabled: true, minutes: 19 * 60);
+  const late = Reminder(enabled: true, minutes: 22 * 60 + 30);
+
+  Streak streak({bool todayDone = false, required DateTime now}) =>
+      Streak.compute([if (todayDone) now.subtract(const Duration(minutes: 1))], now: now);
+
+  test('both Reminders are planned for each of the next days', () {
+    final now = DateTime(2026, 10, 29, 9);
+    final planned = upcomingReminders(
+      [evening, late],
+      streak: streak(now: now),
+      now: now,
+      days: 2,
+    );
+
+    expect(planned.map((r) => r.at), [
+      DateTime(2026, 10, 29, 19),
+      DateTime(2026, 10, 29, 22, 30),
+      DateTime(2026, 10, 30, 19),
+      DateTime(2026, 10, 30, 22, 30),
+    ]);
+    expect(planned.map((r) => r.id).toSet(), hasLength(4));
+  });
+
+  test('a done day gets no Reminders, and times already past are skipped', () {
+    final now = DateTime(2026, 10, 29, 20);
+    final done = upcomingReminders(
+      [evening, late],
+      streak: streak(todayDone: true, now: now),
+      now: now,
+      days: 2,
+    );
+    final open = upcomingReminders(
+      [evening, late],
+      streak: streak(now: now),
+      now: now,
+      days: 1,
+    );
+
+    expect(done.map((r) => r.at), [DateTime(2026, 10, 30, 19), DateTime(2026, 10, 30, 22, 30)]);
+    expect(open.map((r) => r.at), [DateTime(2026, 10, 29, 22, 30)]);
+  });
+
+  test('a switched-off Reminder is never planned', () {
+    final now = DateTime(2026, 10, 29, 9);
+    final planned = upcomingReminders(
+      [evening, const Reminder(enabled: false, minutes: 22 * 60 + 30)],
+      streak: streak(now: now),
+      now: now,
+      days: 2,
+    );
+
+    expect(planned.map((r) => r.at.hour), [19, 19]);
+  });
+
+  test('only today\'s Reminders mention the running Streak; later ones cannot know it', () {
+    final now = DateTime(2026, 10, 29, 9);
+    final s = Streak.compute([DateTime(2026, 10, 27, 18), DateTime(2026, 10, 28, 18)], now: now);
+
+    final planned = upcomingReminders([evening], streak: s, now: now, days: 2);
+
+    expect(planned.map((r) => r.streakDays), [2, null]);
+  });
+}