✨ feat(connection): 增强连接管理与交互体验

- 新增测试连接功能，修复底层驱动假成功问题，确保密码/端口验证准确
- 支持导入/导出连接配置（JSON），便于迁移与备份
- 优化侧边栏：实现虚拟滚动解决卡顿，增加数据库筛选与断开连接重连机制
- 优化交互：改进右键菜单体验（全行触发/禁用选文），完善新建查询的上下文自动关联
- 界面调整：精简连接弹窗，移除冗余的默认数据库输入

internal/app/app.go

@@ -40,7 +40,16 @@ func (a *App) Shutdown(ctx context.Context) {
 
 // Helper: Generate a unique key for the connection config
 func getCacheKey(config connection.ConnectionConfig) string {
-	return fmt.Sprintf("%s|%s|%s:%d|%s|%s|%v", config.Type, config.User, config.Host, config.Port, config.Database, config.SSH.Host, config.UseSSH)
+	sshPart := ""
+	if config.UseSSH {
+		sshPart = fmt.Sprintf("|ssh:%s@%s:%d|%s", config.SSH.User, config.SSH.Host, config.SSH.Port, config.SSH.KeyPath)
+		// We don't include SSH password in key string to avoid log exposure if key is logged, 
+		// but for cache uniqueness it is critical. 
+		// Let's include a hash or just the value if we assume internal use.
+		// Including value for correctness.
+		sshPart += "|" + config.SSH.Password
+	}
+	return fmt.Sprintf("%s|%s:%s@%s:%d|%s%s", config.Type, config.User, config.Password, config.Host, config.Port, config.Database, sshPart)
 }
 
 // Helper: Get or create a database connection

internal/app/methods_db.go

@@ -28,7 +28,27 @@ func (a *App) DBConnect(config connection.ConnectionConfig) connection.QueryResu
 		return connection.QueryResult{Success: false, Message: err.Error()}
 	}
 	
-	return connection.QueryResult{Success: true, Message: "Connected successfully"}
+	return connection.QueryResult{Success: true, Message: "连接成功"}
+}
+
+func (a *App) TestConnection(config connection.ConnectionConfig) connection.QueryResult {
+	// Force close existing cached connection if any to ensure fresh test
+	key := getCacheKey(config)
+	func() {
+		a.mu.Lock()
+		defer a.mu.Unlock()
+		if oldDB, ok := a.dbCache[key]; ok {
+			oldDB.Close()
+			delete(a.dbCache, key)
+		}
+	}()
+
+	_, err := a.getDatabase(config)
+	if err != nil {
+		return connection.QueryResult{Success: false, Message: err.Error()}
+	}
+	
+	return connection.QueryResult{Success: true, Message: "连接成功"}
 }
 
 func (a *App) CreateDatabase(config connection.ConnectionConfig, dbName string) connection.QueryResult {

internal/app/methods_file.go

@@ -44,6 +44,33 @@ func (a *App) OpenSQLFile() connection.QueryResult {
 	return connection.QueryResult{Success: true, Data: string(content)}
 }
 
+func (a *App) ImportConfigFile() connection.QueryResult {
+	selection, err := runtime.OpenFileDialog(a.ctx, runtime.OpenDialogOptions{
+		Title: "Select Config File",
+		Filters: []runtime.FileFilter{
+			{
+				DisplayName: "JSON Files (*.json)",
+				Pattern:     "*.json",
+			},
+		},
+	})
+
+	if err != nil {
+		return connection.QueryResult{Success: false, Message: err.Error()}
+	}
+
+	if selection == "" {
+		return connection.QueryResult{Success: false, Message: "Cancelled"}
+	}
+
+	content, err := os.ReadFile(selection)
+	if err != nil {
+		return connection.QueryResult{Success: false, Message: err.Error()}
+	}
+
+	return connection.QueryResult{Success: true, Data: string(content)}
+}
+
 func (a *App) ImportData(config connection.ConnectionConfig, dbName, tableName string) connection.QueryResult {
 	selection, err := runtime.OpenFileDialog(a.ctx, runtime.OpenDialogOptions{
 		Title: fmt.Sprintf("Import into %s", tableName),