fix(trekbrief): the review stamp covers only text the reviewer saw

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

tests/validators/brief-review-stamp-order.test.mjs

@@ -0,0 +1,56 @@
+// tests/validators/brief-review-stamp-order.test.mjs
+// /trekbrief stamps only text the reviewer saw. A `small` brief gets one
+// review; its gaps are written as assumptions. When that writing came before
+// the stamp, the stamp covered text no reviewer read and /trekplan skipped its
+// own review. The gaps are now written after the stamp, on purpose, so the
+// stamp reads stale and /trekplan reviews the brief once more.
+
+import { test } from 'node:test';
+import { strict as assert } from 'node:assert';
+import { readFileSync } from 'node:fs';
+import { dirname, join } from 'node:path';
+import { fileURLToPath } from 'node:url';
+import { stampBriefReview, checkBriefReview } from '../../lib/validators/brief-review-stamp.mjs';
+
+const HERE = dirname(fileURLToPath(import.meta.url));
+const ROOT = join(HERE, '..', '..');
+const brief = readFileSync(join(ROOT, 'commands', 'trekbrief.md'), 'utf8');
+
+const STAMP = 'brief-review-stamp.mjs --stamp';
+const GAPS = "Class `small` only: now write the reviewer's gaps";
+const PASS_START = '**If gate passes:**';
+const PASS_END = '**If gate fails AND iteration count < the class cap:**';
+
+function unique(text, needle) {
+  const at = text.indexOf(needle);
+  assert.ok(at >= 0, `found: ${needle}`);
+  assert.equal(text.lastIndexOf(needle), at, `unique in commands/trekbrief.md: ${needle}`);
+  return at;
+}
+
+test('trekbrief: the stamp comes before the small-class gaps are written, both in the passed-gate branch', () => {
+  const start = unique(brief, PASS_START);
+  const end = unique(brief, PASS_END);
+  const stamp = unique(brief, STAMP);
+  const gaps = unique(brief, GAPS);
+  assert.ok(start < end, 'passed-gate branch precedes the failed-gate branch');
+  assert.ok(start < stamp && stamp < end, 'the stamp sits in the passed-gate branch');
+  assert.ok(start < gaps && gaps < end, 'the gaps instruction sits in the passed-gate branch');
+  assert.ok(stamp < gaps, 'order: stamp, then the small-class gaps');
+  const after = brief.slice(gaps, end);
+  assert.match(after, /They come after the stamp on purpose/);
+  assert.match(after, /## Open Questions \/ Assumptions/);
+});
+
+test('guard: stamping a brief and then appending an assumption reads as stale', () => {
+  const text = [
+    '---', 'type: trekbrief', 'brief_version: "2.2"', 'task: t', 'slug: s', 'ceremony: small', '---', '',
+    '## TL;DR', '', 'A toy.', '', '## Intent', '', 'Why it matters.', '', '## Goal', '', 'What.', '',
+    '## Open Questions / Assumptions', '', '- None.', '',
+  ].join('\n');
+  const s = stampBriefReview(text);
+  assert.equal(s.stamped, true);
+  assert.equal(checkBriefReview(s.text).state, 'current');
+  const withGap = s.text + '- Assumed, not asked: the setting defaults to off (reviewer gap).\n';
+  assert.equal(checkBriefReview(withGap).state, 'stale');
+});