Add multi-image support for task completions and documents

- Add TaskCompletionImage and DocumentImage models with one-to-many relationships
- Update admin panel to display images for completions and documents
- Add image arrays to API request/response DTOs
- Update repositories with Preload("Images") for eager loading
- Fix seed SQL execution to use raw SQL instead of prepared statements
- Fix table names in seed file (admin_users, push_notifications_*)
- Add comprehensive seed test data with 34 completion images and 24 document images
- Add subscription limitations admin feature with toggle
- Update admin sidebar with limitations link

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

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

internal/repositories/task_repo.go

@@ -435,6 +435,7 @@ func (r *TaskRepository) FindCompletionByID(id uint) (*models.TaskCompletion, er
 	var completion models.TaskCompletion
 	err := r.db.Preload("Task").
 		Preload("CompletedBy").
+		Preload("Images").
 		First(&completion, id).Error
 	if err != nil {
 		return nil, err
@@ -446,6 +447,7 @@ func (r *TaskRepository) FindCompletionByID(id uint) (*models.TaskCompletion, er
 func (r *TaskRepository) FindCompletionsByTask(taskID uint) ([]models.TaskCompletion, error) {
 	var completions []models.TaskCompletion
 	err := r.db.Preload("CompletedBy").
+		Preload("Images").
 		Where("task_id = ?", taskID).
 		Order("completed_at DESC").
 		Find(&completions).Error
@@ -457,6 +459,7 @@ func (r *TaskRepository) FindCompletionsByUser(userID uint, residenceIDs []uint)
 	var completions []models.TaskCompletion
 	err := r.db.Preload("Task").
 		Preload("CompletedBy").
+		Preload("Images").
 		Joins("JOIN task_task ON task_task.id = task_taskcompletion.task_id").
 		Where("task_task.residence_id IN ?", residenceIDs).
 		Order("completed_at DESC").
@@ -466,9 +469,21 @@ func (r *TaskRepository) FindCompletionsByUser(userID uint, residenceIDs []uint)
 
 // DeleteCompletion deletes a task completion
 func (r *TaskRepository) DeleteCompletion(id uint) error {
+	// Delete images first
+	r.db.Where("completion_id = ?", id).Delete(&models.TaskCompletionImage{})
 	return r.db.Delete(&models.TaskCompletion{}, id).Error
 }
 
+// CreateCompletionImage creates a new completion image
+func (r *TaskRepository) CreateCompletionImage(image *models.TaskCompletionImage) error {
+	return r.db.Create(image).Error
+}
+
+// DeleteCompletionImage deletes a completion image
+func (r *TaskRepository) DeleteCompletionImage(id uint) error {
+	return r.db.Delete(&models.TaskCompletionImage{}, id).Error
+}
+
 // TaskStatistics represents aggregated task statistics
 type TaskStatistics struct {
 	TotalTasks        int