[CI Failure] Npgsql (windows-latest) 'Build test project' step fails with generic exit code 1, unrelated to PR changes

## Build Information

Build: https://github.com/microsoft/aspire/actions/runs/34379133718
Build error leg: Tests / No-package tests (regular, Aspire.Hosting.Testing.Tests, Hosting.Testing, Hosting.Testing, tests/... / Hosting.Testing (ubuntu-latest)
Pull request: #19893

## Error Message

```
Process completed with exit code 1. (Build test project step failed for Aspire.Npgsql.Tests on windows-latest; job logs unavailable: 'Failed to fetch logs for job'). No TRX test failures extracted for this job. PR only modifies Aspire.Cli agent init code, unrelated to Npgsql test project build.
```

## Description

Npgsql (windows-latest) 'Build test project' step fails with generic exit code 1, unrelated to PR changes

**Type**: infra-failure

## Occurrences

| Date | Build | Job | PR |
|------|-------|-----|----|
| 2026-09-09 | [34379133718](https://github.com/microsoft/aspire/actions/runs/34379133718) | Tests / No-package tests (regular, Aspire.Hosting.Testing.Tests, Hosting.Testing, Hosting.Testing, tests/... / Hosting.Testing (ubuntu-latest) | #19893 |

Start with build 34379133718 and the Aspire.Npgsql.Tests “Build test project” step on windows-latest; the payload notes that job logs could not be fetched and no TRX failures were extracted. Compare the failing job with the referenced PR and determine why the test project exits with code 1; done means the CI build completes successfully and the cause is documented.

Written by the indexing model from the issue text.