[bradleyshep]

Description of Changes

Fix blocking scoring and cleanup that can delay benchmark health checks and incorrectly report the server as unavailable.

• Move scoring and cancellation cleanup off the async task.
• Finish blocking work before stopping the server.
• Upload server logs and resource diagnostics as CI artifacts.
• Fix Register name collisions in two C# references and their prompts.
• Add regression tests.

API and ABI breaking changes

No product API or ABI changes. Two C# benchmark tasks now use RegisterUser instead of Register.

Rollback safety impact

n/a

Expected complexity level and risk

2/5. Limited to the benchmark runner, diagnostics, and C# reference tasks. No production server behavior changes.

Testing

• All 69 local unit tests pass.
• Regression tests fail with the old blocking behavior and pass with the fix.
• Both C# fixes compile against the failed run's SDK.
• Clippy, formatting, and diff checks pass.
• Validate on Linux CI.
• Run a small benchmark without uploads and inspect diagnostics.

Benchmarks have not been rerun. The weekly workflow remains disabled.