Scale Set Job To Runner Assignment [Public Preview]

### Value Prop
With Scale Set Job To Runner Assignment, customers using GitHub Actions Scale Sets can automatically distribute jobs to the most suitable runners, making large-scale CI/CD workflows faster and more efficient. This feature reduces wait times and resource waste by ensuring jobs are assigned where they can run best, even as demand changes.

### Expected Outcome
We want customers to experience smoother, more reliable automation at scale, with less manual intervention and fewer workflow bottlenecks. By improving job placement and scheduling, this release aims to help teams deliver software faster and more predictably.

从 issue 正文开始，其中描述了适用于 GitHub Actions Scale Sets 的 Scale Set Job To Runner Assignment 及其预期的调度收益。payload 未列出任何文件、测试、入口点或具体的实现任务，因此除了交付所描述的功能之外，没有指定其他完成标准。

由索引模型根据 Issue 内容生成。