feat: initial commit - Habo habit tracking app

- Complete MVP with Repository Pattern, SQLite storage
- Provider + ChangeNotifier state management
- Navigation 2.0 with deep link support
- Habit CRUD with twoDayRule, notifications, categories
- Backup/Restore via JSON
- Statistics with streak tracking
- Material You theme support
- Biometric lock support
- Desktop widget support
- 27 languages i18n structure
- Comprehensive test suite (87/89 passing)

lib/repositories/event_repository.dart

@@ -0,0 +1,11 @@
+import 'dart:collection';
+
+abstract class EventRepository {
+  Future<List<List>> getEventsForHabit(int habitId);
+  Future<SplayTreeMap<DateTime, List>> getEventsMapForHabit(int habitId);
+  Future<void> insertEvent(int habitId, DateTime date, List event);
+  Future<void> deleteEvent(int habitId, DateTime date);
+  Future<void> deleteAllEventsForHabit(int habitId);
+  Future<void> insertEventsForHabit(int habitId, Map<DateTime, List> events);
+  Future<void> deleteAllEvents();
+}