fix(软删除): 增强错误处理，确保软删除操作中的错误类型正确

backend/ent/schema/mixins/soft_delete.go

@@ -155,7 +155,12 @@ func mutateWithClient(ctx context.Context, m ent.Mutation, fallback ent.Mutator)
 	value := results[0].Interface()
 	var err error
 	if !results[1].IsNil() {
-		err = results[1].Interface().(error)
+		errValue := results[1].Interface()
+		typedErr, ok := errValue.(error)
+		if !ok {
+			return nil, fmt.Errorf("soft delete: unexpected error type %T for %T", errValue, m)
+		}
+		err = typedErr
 	}
 	if err != nil {
 		return nil, err