feat: 添加Neo4j图数据库支持及前端代码重构

- 新增 Neo4j 图数据库 handler、service、model
- 后端添加 SaveGraph API 接口
- 前端 Database.vue 重构，拆分为独立组件
- 新增 web/src/views/database/ 组件目录
- 删除临时文件 (temp_*.go)
- 添加 Neo4j 相关 API 需求文档

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

server/internal/service/database_service.go

@@ -259,6 +259,27 @@ func (s *DatabaseService) Check(req model.CheckRequest) (*model.CheckResponse, e
 	var db *sql.DB
 	var err error
 
+	// Neo4j 处理
+	if dbType == "neo4j" {
+		log.Printf("[Check] 检测到 Neo4j 类型，使用图数据库连接...")
+		neo4jService := NewNeo4jService(s.repo)
+		graph, err := neo4jService.GetGraphOverview(req)
+		if err != nil {
+			log.Printf("[Check] Neo4j 连接失败: %v", err)
+			return &model.CheckResponse{
+				Success: false,
+				Message: fmt.Sprintf("neo4j connection failed: %v", err),
+			}, nil
+		}
+		log.Printf("[Check] Neo4j 连接成功，获取到 %d 个标签", len(graph.Labels))
+		return &model.CheckResponse{
+			Success:  true,
+			Message:  "connection successful",
+			Graphs:   graph,
+			Database: req.Database,
+		}, nil
+	}
+
 	switch dbType {
 	case "mysql":
 		db, err = sql.Open("mysql", dsn)
@@ -684,6 +705,92 @@ func (s *DatabaseService) Update(id string, req model.UpdateDatabaseRequest) (*m
 	return s.repo.FindByID(id)
 }
 
+// SaveGraph 保存图谱信息
+func (s *DatabaseService) SaveGraph(req model.SaveGraphRequest) (*model.SaveGraphResponse, error) {
+	log.Printf("[SaveGraph] 保存图谱信息, databaseId=%s, databaseName=%s", req.DatabaseID, req.DatabaseName)
+
+	// 检查数据库是否存在
+	_, err := s.repo.FindByID(req.DatabaseID)
+	if err != nil {
+		// 如果不存在，创建一个新的
+		if err == ErrDatabaseNotFound {
+			// 创建新的数据库记录
+			dbType := "neo4j"
+			// 从 URI 解析 host 和 port
+			host := "localhost"
+			port := 7687
+			if req.URI != "" {
+				uri := strings.TrimPrefix(req.URI, "bolt://")
+				uri = strings.TrimPrefix(uri, "neo4j://")
+				if idx := strings.Index(uri, ":"); idx > 0 {
+					host = uri[:idx]
+					fmt.Sscanf(uri[idx+1:], "%d", &port)
+				}
+			}
+
+			// 将 labels 和 relationshipTypes 转为 JSON 字符串
+			labelsJSON, _ := json.Marshal(req.Labels)
+			relJSON, _ := json.Marshal(req.RelationshipTypes)
+
+			info := &model.DatabaseInfo{
+				ID:                req.DatabaseID,
+				Name:              req.DatabaseName,
+				DBType:            dbType,
+				Host:              host,
+				Port:              port,
+				Username:          req.Username,
+				URI:               req.URI,
+				GraphLabels:       string(labelsJSON),
+				GraphRelationship: string(relJSON),
+				SelectedLabel:     req.SelectedLabel,
+			}
+
+			if err := s.repo.Create(info); err != nil {
+				log.Printf("[SaveGraph] 创建失败: %v", err)
+				return &model.SaveGraphResponse{
+					Success: false,
+					Message: fmt.Sprintf("创建失败: %v", err),
+				}, err
+			}
+
+			return &model.SaveGraphResponse{
+				Success: true,
+				Message: "保存成功",
+			}, nil
+		}
+		log.Printf("[SaveGraph] 查询失败: %v", err)
+		return &model.SaveGraphResponse{
+			Success: false,
+			Message: fmt.Sprintf("查询失败: %v", err),
+		}, err
+	}
+
+	// 更新现有记录
+	labelsJSON, _ := json.Marshal(req.Labels)
+	relJSON, _ := json.Marshal(req.RelationshipTypes)
+
+	updates := map[string]interface{}{
+		"uri":                  req.URI,
+		"username":             req.Username,
+		"graph_labels":         string(labelsJSON),
+		"graph_relationship":  string(relJSON),
+		"selected_label":      req.SelectedLabel,
+	}
+
+	if err := s.repo.UpdateFields(req.DatabaseID, updates); err != nil {
+		log.Printf("[SaveGraph] 更新失败: %v", err)
+		return &model.SaveGraphResponse{
+			Success: false,
+			Message: fmt.Sprintf("更新失败: %v", err),
+		}, err
+	}
+
+	return &model.SaveGraphResponse{
+		Success: true,
+		Message: "保存成功",
+	}, nil
+}
+
 // fillFieldMappings 填充字段映射到表结构中
 func (s *DatabaseService) fillFieldMappings(databaseID string, tables []model.TableDDLInfo) {
 	// 从数据库中获取该数据库下所有子表的字段映射