fix(be): 任务完成统计与留痕改用 PlanTask（DailyTask 已空）

- TogglePlanTask：完成无 sheet_type 的任务时补一条 note 记录，
  首页/计划页两条路径都统一留痕（ToggleTask 委托它）；去掉前端重复建记录
- 报告页「完成任务」原来统计空的 DailyTask 恒为 0，改成经 plan 关联
  统计 PlanTask 本周完成数；用户汇总的 tasksDone 同改
- 首页今日完成度 todayCompletionPct 同样从 DailyTask 改成今日 PlanTask

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

pets-be/internal/service/report.go

@@ -26,9 +26,10 @@ func (s *Service) GetWeeklyReport(userID, petID string) (*WeeklyReport, error) {
 	}
 	weekAgo := time.Now().AddDate(0, 0, -7)
 
+	// 任务已并成 PlanTask（DailyTask 表已空），要经 plan 关联到宠物来统计本周完成数
 	var tasksCompleted int64
-	s.db.Model(&model.DailyTask{}).
-		Where("pet_id = ? AND done = ? AND updated_at >= ?", petID, true, weekAgo).
+	s.db.Model(&model.PlanTask{}).
+		Where("plan_id IN (SELECT id FROM sundynix_plans WHERE pet_id = ?) AND done = ? AND updated_at >= ?", petID, true, weekAgo).
 		Count(&tasksCompleted)
 
 	// 体重增长：最近 7 天最新 - 最早
@@ -215,7 +216,9 @@ func (s *Service) GetPoster(userID, petID string) (*Poster, error) {
 		return nil, err
 	}
 	var tasksDone, weightRecs, vaccineRecs int64
-	s.db.Model(&model.DailyTask{}).Where("pet_id = ? AND done = ?", petID, true).Count(&tasksDone)
+	s.db.Model(&model.PlanTask{}).
+		Where("plan_id IN (SELECT id FROM sundynix_plans WHERE pet_id = ?) AND done = ?", petID, true).
+		Count(&tasksDone)
 	s.db.Model(&model.HealthRecord{}).Where("pet_id = ? AND type = ?", petID, model.RecordWeight).Count(&weightRecs)
 	s.db.Model(&model.HealthRecord{}).Where("pet_id = ? AND type = ?", petID, model.RecordVaccine).Count(&vaccineRecs)