refactor: 重构neo4j服务

backend/internal/model/response.go

@@ -1,5 +1,11 @@
 package model
 
+// ErrorResponse represents a standardized API error response.
+type ErrorResponse struct {
+	Error   string `json:"error" example:"bad_request"`
+	Message string `json:"message" example:"invalid request"`
+}
+
 // CreateNodeRequest creates a new node
 type CreateNodeRequest struct {
 	ID         string                 `json:"id" binding:"required" example:"node_123"`