Awaited deadline oracles get the runner token; sync-over-async tests made async;
nullable child models asserted via ShouldNotBeNull() return values; obsolete SDK
ctors replaced with the telemetry overloads; dead locals/fixture and the redundant
DI PackageReference removed. No suppressions.
Claude-Session: https://claude.ai/code/session_01GT67AEHd2Acv1YPwGfXEoV
Joseph Doherty