fix: 修复一系列问题并生成swagger一键脚本

backend/internal/service/neo4j_fetch.go

@@ -0,0 +1,31 @@
+package service
+
+import (
+	"context"
+
+	"github.com/neo4j/neo4j-go-driver/v5/neo4j"
+
+	"knowledge-graph-backend/internal/model"
+)
+
+func (s *Neo4jService) fetchNodeByID(id string) (model.Node, bool, error) {
+	ctx := context.Background()
+	result, err := neo4j.ExecuteQuery(ctx, s.driver,
+		`MATCH (n {id: $id}) RETURN n LIMIT 1`,
+		map[string]any{"id": id},
+		neo4j.EagerResultTransformer,
+	)
+	if err != nil {
+		return model.Node{}, false, err
+	}
+	if len(result.Records) == 0 {
+		return model.Node{}, false, nil
+	}
+
+	v, _ := result.Records[0].Get("n")
+	n, ok := v.(neo4j.Node)
+	if !ok {
+		return model.Node{}, false, nil
+	}
+	return neo4jNodeToModel(n), true, nil
+}

backend/internal/service/neo4j_service.go

@@ -0,0 +1,13 @@
+package service
+
+import "github.com/neo4j/neo4j-go-driver/v5/neo4j"
+
+// Neo4jService provides graph operations backed by Neo4j.
+type Neo4jService struct {
+	driver neo4j.DriverWithContext
+}
+
+// NewNeo4jService creates a new Neo4j-backed graph service.
+func NewNeo4jService(driver neo4j.DriverWithContext) *Neo4jService {
+	return &Neo4jService{driver: driver}
+}