test(gate-concurrency): drop the archived receipts and replay gate

[tnunamak]

Problem

reference-implementation/docs/receipts/gate-concurrency-20260903.tar.gz held the raw receipts and transcripts from one day of test runs: two runs of the same tree, one at file-concurrency cap 2 and one at cap 8. A test under reference-implementation/scripts/evidence/ re-derived each receipt's counts, failure names and digests from those archived bytes, and a path-triggered workflow (.github/workflows/gate-concurrency-evidence.yml) ran that replay whenever any of the five files changed.

That archive is a snapshot of a tree that has since moved on. Replaying it cannot tell you anything about the cap as it behaves today — it only confirms the archived bytes are unchanged, which is a property of the archive rather than of the concurrency cap. Meanwhile the archive carried real cost: 445 KB compressed, about 4 MB unpacked, two near-identical 1.9 MB transcripts, plus a workflow and a 371-line test whose only job was to re-check it. The durable result of that measurement is a handful of numbers, not four megabytes of transcript.

Change

The measurement's lasting content now lives as a table in reference-implementation/docs/gate-concurrency.md: both caps, elapsed times, selected-file and assertion counts, the pass/fail/skip split, the fact that both runs produced the same 396 failure identities, and the exit codes. The document keeps the honest reading of that result — failure-set equality for one pair on one host, not a green suite and not proof either cap is safe — and now states that ongoing CI runs at the current cap are the evidence going forward.

Removed:

• reference-implementation/docs/receipts/gate-concurrency-20260903.tar.gz
• reference-implementation/docs/receipts/gate-concurrency-20260903.summary.json
• reference-implementation/scripts/evidence/gate-concurrency-receipts.test.ts (the directory is now empty and gone)
• .github/workflows/gate-concurrency-evidence.yml

Kept: reference-implementation/scripts/gate-concurrency-receipt.ts and reference-implementation/scripts/gate-concurrency-receipt.test.ts. These are not archive-only. The runner's standalone discovery walks scripts/ as a selection root (COLOCATED_TEST_DIRS in reference-implementation/scripts/run-tests-discovery.ts), so that unit test already runs as part of the main gate — the deleted workflow was not what kept it alive. The replay test under scripts/evidence/ was the opposite case: that walk is non-recursive, so nothing selected it, which is exactly why it needed a dedicated workflow.

One documentation point was worth preserving on its own merits and has been rewritten to stand without the archive: completed_files is derived from the exit code (run-tests.ts writes failed ? 0 : results.length), so it reads 0 for any run that exits non-zero and is not an observed per-file completion count.

How to verify

Confirm the kept test still passes:

cd reference-implementation
node --test --experimental-strip-types scripts/gate-concurrency-receipt.test.ts

Expect 10 passing, 0 failing.

Confirm test discovery is intact — that the kept test is still selected and that nothing points at a deleted file:

cd reference-implementation
node --experimental-strip-types -e '
const root = process.cwd(); const fs = require("node:fs");
import(root + "/scripts/run-tests-discovery.ts").then(async (m) => {
  const rel = await m.discoverTestFiles(root, root + "/test");
  console.log("discovered:", rel.length);
  console.log("kept test selected:", rel.some(f => f.includes("gate-concurrency-receipt.test.ts")));
  console.log("selected-but-missing:", rel.filter(f => !fs.existsSync(root + "/" + f)));
});'

Expect 1034 discovered, the kept test selected, and an empty missing list.

Confirm no reference to a removed artifact survives anywhere:

grep -rn "gate-concurrency-20260903\|scripts/evidence\|gate-concurrency-evidence" . \
  | grep -v node_modules | grep -v "\.git/"

Expect no output.

This commit is scoped test(gate-concurrency) so it cuts no package release: .releaserc.yaml releases only on feat/fix/perf/revert (or a breaking marker) and only for the connector-protocol, collector-runtime or local-collector scopes, so the type and the scope each independently rule out a publish.

Assisted-by: AI