Question / Improvement: Incremental publishing of devcontainer features and `devcontainer-collection.json`

## Description

We’re exploring whether the Dev Container CLI is intended to support publishing devcontainer features **one by one**.

When features are published individually, `devcontainer-collection.json` is regenerated each time and ends up containing **only the last published feature**. When all features are published together, the collection file is generated correctly.

This behavior seems consistent and intentional, so this is not a bug report, more a question and possible improvement discussion.

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## Question / Improvement Idea

Is publishing features incrementally an intended workflow?

If this use case is in scope, would it make sense to support:
- Merging newly published features into an existing `devcontainer-collection.json`, or
- A flag or documented approach for incremental publishing?

The motivation is mainly CI/CD robustness, where publishing one feature should not block others.

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If incremental publishing is intentionally unsupported, clarification or documentation around this would also be very helpful.

未指定任何文件、测试或入口点。首先复现增量发布和一次性发布所有功能，然后跟踪 devcontainer-collection.json 的生成方式；明确是否支持增量发布、条目应如何合并，或文档应说明什么。

由索引模型根据 Issue 内容生成。