Changes between 0.4.0-alpha.3 and v1.0.0.0: Null values changed to '' and 24h time values to 12h time values

### Command that triggered the bug

apiops publish

### Expected behavior

The extracted values are fine but after publish the values are changes:
Example:
Source JSON:
"firstSeen": "2026-07-11T14:01:26.0000000+00:00",
"lastSeen": "2026-07-11T14:58:54.0000000+00:00",
"zone": null,
Published values:
"firstSeen": "2026-07-11T02:01:26.0000000+00:00",
"lastSeen": "2026-07-11T02:58:54.0000000+00:00",
"zone": '',

### Actual behavior

Null values get replaced with empty string '' and 24h time values are replaced with 12h format values with no AM/PM flag.

### apiops CLI version

1.0.0.0

### Environment details

command runs in a gitlab pipeline on self hosted gitlab runner image: mcr.microsoft.com/dotnet/sdk:6.0
Nodejs version node-v22.14.0-linux-x64

### CI/CD environment

Other

### Is this bug blocking you?

Yes

首先使用 issue 中的源 JSON 和环境详细信息重现 `apiops publish`，然后跟踪序列化提取值的发布路径。发布的输出保留 null 值和原始的 24 小时制时间值后，即视为完成；为这两种情况添加或更新回归测试。

由索引模型根据 Issue 内容生成。