feat(daily): pure 7-day login-calendar logic + reward table

lib/game/daily/daily_reward.dart

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+// lib/game/daily/daily_reward.dart
+import '../models/booster.dart';
+
+/// The result of evaluating the calendar for "today".
+class DailyResolution {
+  const DailyResolution({required this.claimable, required this.day});
+  final bool claimable;
+  final int day; // 1..7, the day to show/grant
+}
+
+/// Pure 7-day login-calendar logic. No storage or clock — callers pass the
+/// persisted state and today's date so it is fully unit-testable.
+class DailyRewardCalendar {
+  const DailyRewardCalendar();
+
+  static const int cycle = 7;
+
+  String ymd(DateTime date) {
+    final m = date.month.toString().padLeft(2, '0');
+    final d = date.day.toString().padLeft(2, '0');
+    return '${date.year}-$m-$d';
+  }
+
+  DailyResolution resolve({
+    required String? lastClaimedYmd,
+    required int storedDay,
+    required DateTime today,
+  }) {
+    final todayYmd = ymd(today);
+    if (lastClaimedYmd == todayYmd) {
+      return DailyResolution(claimable: false, day: storedDay);
+    }
+    final yesterday = ymd(today.subtract(const Duration(days: 1)));
+    final int day;
+    if (lastClaimedYmd == yesterday) {
+      day = (storedDay % cycle) + 1; // advance, wrapping 7 -> 1
+    } else {
+      day = 1; // first ever, or a day was missed
+    }
+    return DailyResolution(claimable: true, day: day);
+  }
+
+  /// Boosters granted for a given calendar day (1..7). Tunable.
+  Map<BoosterType, int> rewardFor(int day) {
+    switch (day) {
+      case 1:
+        return {BoosterType.hammer: 1};
+      case 2:
+        return {BoosterType.shuffle: 1};
+      case 3:
+        return {BoosterType.lineBomb: 1};
+      case 4:
+        return {BoosterType.hammer: 1, BoosterType.shuffle: 1};
+      case 5:
+        return {BoosterType.shuffle: 1, BoosterType.lineBomb: 1};
+      case 6:
+        return {BoosterType.hammer: 1, BoosterType.lineBomb: 1};
+      case 7:
+      default:
+        return {
+          BoosterType.hammer: 2,
+          BoosterType.shuffle: 2,
+          BoosterType.lineBomb: 2,
+        };
+    }
+  }
+}

test/game/daily/daily_reward_test.dart

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+import 'package:block_seasons/game/daily/daily_reward.dart';
+import 'package:block_seasons/game/models/booster.dart';
+import 'package:flutter_test/flutter_test.dart';
+
+void main() {
+  final cal = DailyRewardCalendar();
+
+  DateTime d(int day) => DateTime(2026, 6, day);
+
+  test('first ever claim is day 1', () {
+    final r = cal.resolve(lastClaimedYmd: null, storedDay: 0, today: d(18));
+    expect(r.claimable, isTrue);
+    expect(r.day, 1);
+  });
+
+  test('claiming again the same day is not claimable', () {
+    final r = cal.resolve(
+        lastClaimedYmd: '2026-06-18', storedDay: 1, today: d(18));
+    expect(r.claimable, isFalse);
+  });
+
+  test('a consecutive day advances the calendar', () {
+    final r = cal.resolve(
+        lastClaimedYmd: '2026-06-18', storedDay: 3, today: d(19));
+    expect(r.claimable, isTrue);
+    expect(r.day, 4);
+  });
+
+  test('day 7 wraps back to day 1', () {
+    final r = cal.resolve(
+        lastClaimedYmd: '2026-06-18', storedDay: 7, today: d(19));
+    expect(r.day, 1);
+  });
+
+  test('a missed day resets to day 1', () {
+    final r = cal.resolve(
+        lastClaimedYmd: '2026-06-18', storedDay: 4, today: d(20));
+    expect(r.claimable, isTrue);
+    expect(r.day, 1);
+  });
+
+  test('reward table covers days 1..7 and day 7 is the jackpot', () {
+    expect(cal.rewardFor(1), {BoosterType.hammer: 1});
+    expect(cal.rewardFor(7),
+        {BoosterType.hammer: 2, BoosterType.shuffle: 2, BoosterType.lineBomb: 2});
+  });
+
+  test('ymd formats a date as YYYY-MM-DD', () {
+    expect(cal.ymd(DateTime(2026, 6, 7)), '2026-06-07');
+  });
+}