feat(05-01): implement CalendarDao with date-parameterized task queries

- CalendarDao.watchTasksForDate: returns tasks due on a specific calendar day, sorted by name
- CalendarDao.watchOverdueTasks: returns tasks due strictly before reference date, sorted by due date
- Registered CalendarDao in AppDatabase @DriftDatabase annotation
- Generated calendar_dao.g.dart and updated database.g.dart

lib/core/database/database.g.dart

@@ -1246,6 +1246,7 @@ abstract class _$AppDatabase extends GeneratedDatabase {
   late final RoomsDao roomsDao = RoomsDao(this as AppDatabase);
   late final TasksDao tasksDao = TasksDao(this as AppDatabase);
   late final DailyPlanDao dailyPlanDao = DailyPlanDao(this as AppDatabase);
+  late final CalendarDao calendarDao = CalendarDao(this as AppDatabase);
   @override
   Iterable<TableInfo<Table, Object?>> get allTables =>
       allSchemaEntities.whereType<TableInfo<Table, Object?>>();