[tannevaled]

This PR's first commit was built on a false premise and the second undoes
it. Keeping the record rather than rewriting it, because the correction is
the useful part. The net diff is README.md plus one test file — no workflow
change.

I set out to gate the README's conformance total, believing nothing checked it,
and added a CI job around the published conformancefigure. Then I read
readme_conformance_count_test.go: it has
been checking exactly that for weeks, against BASELINE in the same tree, with
no network and no pinned external version — strictly better than what I was
adding. The job is gone.

What actually was ungated: the version

TestReadmeConformanceCountMatchesTheBaseline checks the total. It does not
check the version that total is counted at, and that version selects the
population counted: the move from 3.4.1 to 4.0.9 changed which
ruby_version_is guards admit examples (+144 passing, 27 gone red). The
same number means a different thing at a different version.

TestReadmeRubyVersionMatchesTheRuntime reads rubyVersion from
internal/vm/kernel_introspect.go and checks it both ways:

	what it does	what happens when it can't reach a claim
forward	every present-tense claim must equal it	fewer matches than shapes ⇒ fail
inverse	a line naming a different version must declare itself historical	exemptions are logged, not silent

Both halves are needed, and a deliberate break proved it. With the table
row set to 4.0.8, the forward check named it — while the inverse check
exempted the same 4.0.8, because that line also says "the move from". A
line-granular marker meant for the version left behind covered a wrong
present-tense claim sitting beside it.

README.md:782 claims the runtime reports 4.0.8, kernel_introspect.go says 4.0.9
README.md:782 names 4.0.8 and is exempt: the line says "the move from"
2 present-tense version claim(s) checked against 4.0.9, 3 historical line(s) exempt

Two README corrections, measured not read

It runs 23,672 → It passes. 23,672 is what passes; rbgo runs
considerably more. The figure was right and the verb was not — which is exactly
why the existing numeric gate was green throughout. No check on a number can
see a wrong verb.

"A backtick command holds the interpreter lock" no longer reproduces. The
probe the README itself carried printed frozen in October and prints ran
now, 5 runs out of 5, and rubydiff reports the program AGREE with MRI
4.0.7 — same output, not merely no-longer-compared output. Removed, with no
cause attributed: naming one without a control would be a guess dressed as a
fact.

Timeout.timeout was re-checked on the same pass and still fails open —
rbgo prints returned then nil, MRI 4.0.7 prints raised then 0.3 — so it
stays, now with that measurement beside it.

🤖 Generated with Claude Code

[tannevaled]

Not mergeable, and not because of this change.

test (macos-latest) has been cancelled three times on this commit without
ever acquiring a runner — zero steps, empty log, "runner": "", and attempts 2
and 3 cancelled at 15m01s each, to the second. The other 25 checks are
green. Filed as #890 with the control that rules out the workflow, the label
and the plan: the same job on main at 14:13 UTC got a runner and ran 49
minutes.

Two identical durations are a fixed cap, not a busy pool, so I have stopped
re-running: a fourth attempt would be treating a reproducible cutoff as an
intermittent one. Leaving this open rather than merging on 25 of 26 — the lane
has not said the tests pass, and it has not said they fail either.