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/habit_repository.dart

@@ -0,0 +1,12 @@
+import 'package:habo/habits/habit.dart';
+
+abstract class HabitRepository {
+  Future<List<Habit>> getAllHabits();
+  Future<int> createHabit(Habit habit);
+  Future<void> updateHabit(Habit habit);
+  Future<void> deleteHabit(int id);
+  Future<Habit?> findHabitById(int id);
+  Future<void> updateHabitsOrder(List<Habit> habits);
+  Future<void> deleteAllHabits();
+  Future<void> insertHabits(List<Habit> habits);
+}