Restore and build pass on the self-hosted runner but the test run dies after
~3s — too fast to have executed 306 tests. The suite passes on Windows, in a
clean Linux container, under a 1GB memory cap, in CI's exact step order, and
with the SDK installed to a custom dir without DOTNET_ROOT, so the trigger is
specific to this runner rather than the code.
Adds a one-test host smoke step (separates "host cannot start" from "the suite
takes the host down" using step boundaries, since job logs are not readable via
the API) and disables xUnit collection parallelism for the full run — the same
remedy the frontend already needs (--runInBand) on this resource-flaky runner.
All 306 tests still run; only concurrency changes.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
cesnimda
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