Review follow-ups to 34829ea0.
IMPORTANT - the leak filter had its own flake vector. This test saturates the
thread pool by design, and TimedScriptEvaluator starts its 5s clock at WaitAsync
rather than when the inner Task.Run gets a thread, so a legitimately-enqueued
evaluation can blow the budget while still queued and surface "script timed out
after 5.0s". The reason != exhaustion filter classified that as a raw disposed
escape and hard-failed on it - handing the test back the load-fragility the
reshape removed. Timeouts are now their own bucket, tolerated and rate-bounded
exactly as exhaustions are; a raw disposed escape still fails on first occurrence.
Doc-comment names this second residual vector alongside the exhaustion calibration.
MINOR (scope extension authorised by review) - "evaluator disposed during
evaluation" existed as three unshared literals. Promoted to
ScriptEvalFailureReasons alongside VirtualTagEvalResult in Commons.Engines (the
assembly all three already reference) and referenced from both evaluators and the
test. The timeout prefix joins it, since the test now classifies on it too. String
values are byte-identical - no behaviour change.
Falsified: with a 12ms script budget the race produced real timeouts (3/2695).
Classified as leaks (the pre-review filter) they hard-failed the test 6/6 items;
bucketed as starvation they sit 0.11% under the 10% bound and the test is green.
Joseph Doherty
837d8a17eb