feat(contracts): add TableName and gorm serializer tags to DTOs

backend/core/contracts/task.go

@@ -71,6 +71,11 @@ type TaskExecutionDTO struct {
 	UpdatedAt    time.Time  `json:"updated_at"`
 }
 
+// TableName returns the default table name for TaskExecutionDTO.
+func (TaskExecutionDTO) TableName() string {
+	return "w_task_executions"
+}
+
 // Canonical triggered_by values persisted on task executions and shown in admin UI.
 const (
 	TaskTriggerSystem   = "system"