gate('high-keyword'/'high-token') sat outside the injection guard, so an
errored or empty codegraph_explore still counted as a HIGH-tier success.
The gate telemetry is the measured recall/precision funnel that decides
whether the tiered gate design survives — a delivery failure must degrade
it toward noop-*, not inflate the high tiers. Failures now record
noop-explore-keyword / noop-explore-token. Doc enum updated (including
the noop-vocab-empty outcome the #1142 fix adds next).
Co-authored-by: Claude Fable 5 <noreply@anthropic.com>