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/features/home/data/daily_plan_dao.dart

@@ -0,0 +1,24 @@
+import 'package:drift/drift.dart';
+
+import '../../../core/database/database.dart';
+import '../domain/daily_plan_models.dart';
+
+part 'daily_plan_dao.g.dart';
+
+@DriftAccessor(tables: [Tasks, Rooms, TaskCompletions])
+class DailyPlanDao extends DatabaseAccessor<AppDatabase>
+    with _$DailyPlanDaoMixin {
+  DailyPlanDao(super.attachedDatabase);
+
+  /// Watch all tasks joined with room name, sorted by nextDueDate ascending.
+  Stream<List<TaskWithRoom>> watchAllTasksWithRoomName() {
+    // TODO: implement
+    throw UnimplementedError();
+  }
+
+  /// Count task completions recorded today.
+  Stream<int> watchCompletionsToday({DateTime? today}) {
+    // TODO: implement
+    throw UnimplementedError();
+  }
+}