feat: manually mirror opencoze's code from bytedance

Change-Id: I09a73aadda978ad9511264a756b2ce51f5761adf

backend/api/model/crossdomain/variables/variable_instance.go

@@ -0,0 +1,13 @@
+package variables
+
+import (
+	"github.com/coze-dev/coze-studio/backend/api/model/project_memory"
+)
+
+type UserVariableMeta struct {
+	BizType      project_memory.VariableConnector
+	BizID        string
+	Version      string
+	ConnectorUID string
+	ConnectorID  int64
+}