[CI Failure] GitHub Actions infrastructure: Service Unavailable when resolving action download info

## Build Information

Build: https://github.com/microsoft/aspire/actions/runs/29253519053
Build error leg: Tests / Build native CLI archive (Windows) / Build CLI (win-x64)
Pull request: #18756

## Error Message

```
Failed to resolve action download info. Error: Service Unavailable
##[error]Service Unavailable
##[error]Failed to resolve action download info.
```

## Description

GitHub Actions infrastructure: Service Unavailable when resolving action download info

**Type**: infra-failure

## Occurrences

| Date | Build | Job | PR |
|------|-------|-----|----|
| 2026-07-13 | [29253519053](https://github.com/microsoft/aspire/actions/runs/29253519053) | Tests / Build native CLI archive (Windows) / Build CLI (win-x64) | #18756 |

Start with Actions run 29253519053 and the Tests / Build native CLI archive (Windows) / Build CLI (win-x64) job. Check the reported action-download resolution error and its occurrence history; done means determining whether this is a repository issue or a transient GitHub Actions service failure and documenting the outcome.

Written by the indexing model from the issue text.