init: hgmj server initial commit

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

models/v/adsmod/error.go

@@ -0,0 +1,9 @@
+package adsmod
+
+// ADSNotExistError
+type ADSNotExistError struct {
+}
+
+func (ADSNotExistError) Error() string {
+	return "ads is not exist"
+}