init: hgmj server initial commit

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

models/v/wdordmod/error.go

@@ -0,0 +1,9 @@
+package wdordmod
+
+// OrderNotExistError
+type OrderNotExistError struct {
+}
+
+func (d OrderNotExistError) Error() string {
+	return "order not exist error"
+}