feat(03-01): implement DailyPlanDao with cross-room join query and completion count

- watchAllTasksWithRoomName: innerJoin tasks+rooms, sorted by nextDueDate asc
- watchCompletionsToday: customSelect with readsFrom for proper stream invalidation
- All 7 DAO unit tests pass

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

lib/features/home/data/daily_plan_dao.dart

@@ -11,14 +11,42 @@ class DailyPlanDao extends DatabaseAccessor<AppDatabase>
   DailyPlanDao(super.attachedDatabase);
 
   /// Watch all tasks joined with room name, sorted by nextDueDate ascending.
+  /// Includes ALL tasks (overdue, today, future) -- filtering is done in the
+  /// provider layer to avoid multiple queries.
   Stream<List<TaskWithRoom>> watchAllTasksWithRoomName() {
-    // TODO: implement
-    throw UnimplementedError();
+    final query = select(tasks).join([
+      innerJoin(rooms, rooms.id.equalsExp(tasks.roomId)),
+    ]);
+    query.orderBy([OrderingTerm.asc(tasks.nextDueDate)]);
+
+    return query.watch().map((rows) {
+      return rows.map((row) {
+        final task = row.readTable(tasks);
+        final room = row.readTable(rooms);
+        return TaskWithRoom(
+          task: task,
+          roomName: room.name,
+          roomId: room.id,
+        );
+      }).toList();
+    });
   }
 
   /// Count task completions recorded today.
+  /// Uses customSelect with readsFrom for proper stream invalidation.
   Stream<int> watchCompletionsToday({DateTime? today}) {
-    // TODO: implement
-    throw UnimplementedError();
+    final now = today ?? DateTime.now();
+    final startOfDay = DateTime(now.year, now.month, now.day);
+    final endOfDay = startOfDay.add(const Duration(days: 1));
+
+    return customSelect(
+      'SELECT COUNT(*) AS c FROM task_completions '
+      'WHERE completed_at >= ? AND completed_at < ?',
+      variables: [
+        Variable(startOfDay.millisecondsSinceEpoch ~/ 1000),
+        Variable(endOfDay.millisecondsSinceEpoch ~/ 1000),
+      ],
+      readsFrom: {taskCompletions},
+    ).watchSingle().map((row) => row.read<int>('c'));
   }
 }