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();
+  }
+}

lib/features/home/data/daily_plan_dao.g.dart

@@ -0,0 +1,25 @@
+// GENERATED CODE - DO NOT MODIFY BY HAND
+
+part of 'daily_plan_dao.dart';
+
+// ignore_for_file: type=lint
+mixin _$DailyPlanDaoMixin on DatabaseAccessor<AppDatabase> {
+  $RoomsTable get rooms => attachedDatabase.rooms;
+  $TasksTable get tasks => attachedDatabase.tasks;
+  $TaskCompletionsTable get taskCompletions => attachedDatabase.taskCompletions;
+  DailyPlanDaoManager get managers => DailyPlanDaoManager(this);
+}
+
+class DailyPlanDaoManager {
+  final _$DailyPlanDaoMixin _db;
+  DailyPlanDaoManager(this._db);
+  $$RoomsTableTableManager get rooms =>
+      $$RoomsTableTableManager(_db.attachedDatabase, _db.rooms);
+  $$TasksTableTableManager get tasks =>
+      $$TasksTableTableManager(_db.attachedDatabase, _db.tasks);
+  $$TaskCompletionsTableTableManager get taskCompletions =>
+      $$TaskCompletionsTableTableManager(
+        _db.attachedDatabase,
+        _db.taskCompletions,
+      );
+}