fix(canvas): 创作工作台 - 恢复异步媒体任务并完善输入与预览交互

backend/internal/repository/repository.go

@@ -420,7 +420,7 @@ func (r *Repository) Tasks(userID string, limit int, projectID string, activeOnl
 	if limit <= 0 || limit > 100 {
 		limit = 50
 	}
-	query := r.db.Select("id", "session_id", "project_id", "type", "status", "stage", "progress", "prompt", "operation", "provider", "model", "result_json", "billing_order_id", "attempts", "started_at", "completed_at", "created_at", "updated_at").
+	query := r.db.Select("id", "session_id", "project_id", "type", "status", "stage", "progress", "prompt", "operation", "provider", "model", "input_json", "result_json", "billing_order_id", "attempts", "started_at", "completed_at", "created_at", "updated_at").
 		Where("user_id = ?", userID)
 	if strings.TrimSpace(projectID) != "" {
 		query = query.Where("project_id = ?", strings.TrimSpace(projectID))