Add per-residence overdue_count to API response

Adds overdueCount field to each residence in my-residences endpoint,
enabling the mobile app to show pulsing icons on individual residence
cards that have overdue tasks.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

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

internal/dto/responses/residence.go

@@ -48,6 +48,7 @@ type ResidenceResponse struct {
 	PurchasePrice  *decimal.Decimal        `json:"purchase_price"`
 	IsPrimary      bool                    `json:"is_primary"`
 	IsActive       bool                    `json:"is_active"`
+	OverdueCount   int                     `json:"overdue_count"`
 	CreatedAt      time.Time               `json:"created_at"`
 	UpdatedAt      time.Time               `json:"updated_at"`
 }

internal/repositories/task_repo.go

@@ -502,3 +502,37 @@ func (r *TaskRepository) GetTaskStatistics(residenceIDs []uint) (*TaskStatistics
 		TasksDueNextMonth: int(tasksDueNextMonth),
 	}, nil
 }
+
+// GetOverdueCountByResidence returns a map of residence ID to overdue task count.
+// Uses the task.scopes package for consistent filtering logic.
+func (r *TaskRepository) GetOverdueCountByResidence(residenceIDs []uint) (map[uint]int, error) {
+	if len(residenceIDs) == 0 {
+		return map[uint]int{}, nil
+	}
+
+	now := time.Now().UTC()
+
+	// Query to get overdue count grouped by residence
+	type result struct {
+		ResidenceID uint
+		Count       int64
+	}
+	var results []result
+
+	err := r.db.Model(&models.Task{}).
+		Select("residence_id, COUNT(*) as count").
+		Scopes(task.ScopeForResidences(residenceIDs), task.ScopeOverdue(now)).
+		Group("residence_id").
+		Scan(&results).Error
+	if err != nil {
+		return nil, err
+	}
+
+	// Convert to map
+	countMap := make(map[uint]int)
+	for _, r := range results {
+		countMap[r.ResidenceID] = int(r.Count)
+	}
+
+	return countMap, nil
+}

internal/services/residence_service.go

@@ -113,6 +113,16 @@ func (s *ResidenceService) GetMyResidences(userID uint) (*responses.MyResidences
 			summary.TasksDueNextWeek = stats.TasksDueNextWeek
 			summary.TasksDueNextMonth = stats.TasksDueNextMonth
 		}
+
+		// Get per-residence overdue counts
+		overdueCounts, err := s.taskRepo.GetOverdueCountByResidence(residenceIDs)
+		if err == nil && overdueCounts != nil {
+			for i := range residenceResponses {
+				if count, ok := overdueCounts[residenceResponses[i].ID]; ok {
+					residenceResponses[i].OverdueCount = count
+				}
+			}
+		}
 	}
 
 	return &responses.MyResidencesResponse{