os/glog: 支持纯 json 输出

[yangyanqing]

Is your feature request related to a problem?

Option Yes

Describe the solution you'd like

使用 json 格式输出时

	logger := g.Log()
	logger.SetHandlers(glog.HandlerJson)
	logger.SetCtxKeys("Trace-Id", "Client-IP")

	ctx := context.WithValue(context.Background(), "Trace-Id", "123456789")
	ctx = context.WithValue(ctx, "Client-IP", "1.2.3.4")
	logger.Debug(ctx, g.Map{"uid": 100, "name": "john"})

当前输出为

{
  "Time": "2026-07-02T09:06:53.477+08:00",
  "CtxStr": "123456789, 1.2.3.4",
  "Level": "DEBU",
  "Content": "{\"name\":\"john\",\"uid\":100}"
}

无法直接导入 ES、LTS 等日志分析工具，下面纯 json 的格式才可以

{
  "Time": "2026-07-02T09:06:53.477+08:00",
  "Trace-Id": "123456789",
  "Client-IP": "192.168.2.3",
  "Level": "DEBU",
  "name": "john",
  "uid": 100
}

注：以上仅为展示结构，真正输出必须为单行的 jsonl

Describe alternatives you've considered

在 filebeat 中添加复杂的规则转换

Additional

No response