test(03-01): add failing tests for DailyPlanDao cross-room query and completion count

- 7 failing tests for watchAllTasksWithRoomName and watchCompletionsToday
- DAO stub with UnimplementedError methods registered in AppDatabase
- TaskWithRoom and DailyPlanState model classes defined

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

lib/core/database/database.g.dart

@@ -1245,6 +1245,7 @@ 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);
   @override
   Iterable<TableInfo<Table, Object?>> get allTables =>
       allSchemaEntities.whereType<TableInfo<Table, Object?>>();