fix(ci): run the ship-docsync gate E2E in the evals matrix + silent-skip tripwire

The evals.yml matrix is hand-enumerated and the Run step never exported
EVALS_TIER, so the new whole-file-gated ship-docsync E2E would have
self-skipped even with a row — a hollow green one layer deeper than the
documented rehomed-monolith incident. Add the e2e-ship-docsync row with a
row-level `tier: gate` property, exported as EVALS_TIER by the Run step
(empty = unset for every existing row: all readers are `=== '<tier>'` or
truthiness).

New free tripwire test/evals-workflow-matrix.test.ts ratchets the class:
matrix files must exist; gate-hosting files must have a row; whole-file-gated
matrix files must carry a matching row tier; and the burn-down lists enforce
their own cleanup. It enumerates the PRE-EXISTING holes found while wiring
this (8 gate-hosting files with no row; codex/gemini rows running zero tests;
the pty-plan-smoke row hollow since its files adopted describeE2ETier) —
tracked in TODOS as the CI gate-lane hollow-coverage burn-down.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

test/evals-workflow-matrix.test.ts

@@ -0,0 +1,196 @@
+/**
+ * CI eval-matrix completeness tripwire — kills the silent-skip class where a
+ * gate-tier test exists in the repo but the hand-enumerated matrix in
+ * .github/workflows/evals.yml never runs it, so "gate tier blocks merge" is
+ * quietly false in CI. This has happened before (see the "rehomed from the
+ * deleted pre-split monolith" comment in evals.yml) and was found again on
+ * PR #2700: nine gate-hosting files absent from the matrix, plus matrix rows
+ * whose whole-file tier guards can never fire because the Run step exported
+ * no EVALS_TIER.
+ *
+ * Ratchet, not amnesty: the KNOWN_* lists below enumerate the PRE-EXISTING
+ * gaps with reasons, so no NEW gap can land while the backlog burns down
+ * (same pattern as SCANNER_EXEMPT in egress-receipt-wiring). If you fix a
+ * listed gap (add its matrix row / tier property), this test FAILS until you
+ * remove the entry — stale exemptions are enforced, not decorative.
+ *
+ * Wiring pinned:
+ *  - every matrix `file:` path exists on disk (no stale rows),
+ *  - every gate-hosting paid file (whole-file gate self-gate, or named in the
+ *    dep list of a gate-tier E2E_TOUCHFILES key) appears in the matrix or in
+ *    KNOWN_MATRIX_GAPS,
+ *  - every matrix file with a whole-file tier guard has a matching row-level
+ *    `tier:` property (else the suite self-skips and the job is hollow-green)
+ *    or sits in KNOWN_TIER_UNSET.
+ */
+import { describe, test, expect } from 'bun:test';
+import * as fs from 'fs';
+import * as path from 'path';
+import { E2E_TOUCHFILES, E2E_TIERS } from './helpers/touchfiles-data';
+import { isPaidTestFile } from './helpers/paid-test-set';
+
+const ROOT = path.join(import.meta.dir, '..');
+const WORKFLOW = path.join(ROOT, '.github', 'workflows', 'evals.yml');
+
+/**
+ * Pre-existing gate-hosting files with no matrix row (found 2026-08-26,
+ * PR #2700). Adding a row activates real paid runs on every PR — a cost and
+ * flake-surface decision per file, tracked in TODOS.md ("CI gate-lane
+ * hollow-coverage burn-down"). Fix = add a matrix row (plus `tier: gate` when
+ * the file is whole-file gated), then DELETE the entry here.
+ */
+const KNOWN_MATRIX_GAPS = new Set([
+  'test/skill-e2e-ask-user-question-format-compliance.test.ts',
+  'test/skill-e2e-hermetic-canary.test.ts',
+  'test/skill-e2e-ios.test.ts',
+  'test/skill-e2e-plan-ceo-finding-floor.test.ts',
+  'test/skill-e2e-plan-ceo-plan-mode.test.ts',
+  'test/skill-e2e-plan-design-with-ui.test.ts',
+  'test/skill-e2e-plan-devex-finding-floor.test.ts',
+  'test/skill-e2e-plan-devex-plan-mode.test.ts',
+]);
+
+/**
+ * Matrix files whose whole-file tier guard has no matching row `tier:`
+ * property (pre-existing, found 2026-08-26). Consequences today:
+ *  - codex-e2e / gemini-e2e declare 'periodic' → both jobs run ZERO tests and
+ *    report green on every PR (vestigial rows; the periodic cron lane owns
+ *    these suites).
+ *  - the two PTY plan-mode smokes declare 'gate' → the e2e-pty-plan-smoke job
+ *    spends ~7 min on container setup and skill registration, then bun test
+ *    skips every describe — hollow-green since the files adopted
+ *    describeE2ETier.
+ * Fixing either means deliberately (re)activating paid suites on every PR —
+ * tracked in the same TODOS burn-down. Fix = add `tier:` to the row (or
+ * delete the vestigial row), then DELETE the entry here.
+ */
+const KNOWN_TIER_UNSET = new Map([
+  ['test/codex-e2e.test.ts', 'periodic'],
+  ['test/gemini-e2e.test.ts', 'periodic'],
+  ['test/skill-e2e-office-hours-auto-mode.test.ts', 'gate'],
+  ['test/skill-e2e-plan-mode-no-op.test.ts', 'gate'],
+]);
+
+interface MatrixRow {
+  name: string;
+  files: string[];
+  tier?: string;
+}
+
+/** Parse the `matrix: suite:` rows (name / file / optional tier) from evals.yml. */
+function parseMatrixRows(source: string): MatrixRow[] {
+  const rows: MatrixRow[] = [];
+  let current: MatrixRow | null = null;
+  for (const line of source.split('\n')) {
+    const name = line.match(/^\s+- name: (\S+)\s*$/);
+    if (name) {
+      if (current) rows.push(current);
+      current = { name: name[1], files: [] };
+      continue;
+    }
+    if (!current) continue;
+    const file = line.match(/^\s+file: (.+?)\s*$/);
+    if (file) current.files.push(...file[1].trim().split(/\s+/));
+    const tier = line.match(/^\s+tier: (\S+)\s*$/);
+    if (tier) current.tier = tier[1];
+    // `steps:` ends the strategy block — stop before step-level keys leak in.
+    if (/^\s{4}steps:\s*$/.test(line)) break;
+  }
+  if (current) rows.push(current);
+  return rows.filter((r) => r.files.length > 0);
+}
+
+const wholeFileTier = (source: string): string | null => {
+  const m =
+    /\b(?:describeE2ETier|e2eTierEnabled)\(\s*['"`](gate|periodic)['"`]/.exec(source) ||
+    /EVALS_TIER\s*===\s*['"`](gate|periodic)['"`]/.exec(source);
+  return m ? m[1] : null;
+};
+
+const workflowSource = fs.readFileSync(WORKFLOW, 'utf-8');
+const rows = parseMatrixRows(workflowSource);
+const matrixFiles = new Map<string, MatrixRow>();
+for (const row of rows) for (const f of row.files) matrixFiles.set(f, row);
+
+const paidFiles = fs
+  .readdirSync(path.join(ROOT, 'test'))
+  .filter((f) => f.endsWith('.test.ts'))
+  .map((f) => `test/${f}`)
+  .filter(isPaidTestFile);
+
+describe('evals.yml matrix completeness (gate-lane silent-skip tripwire)', () => {
+  test('matrix parse sanity: rows and known suites present', () => {
+    expect(rows.length).toBeGreaterThanOrEqual(15);
+    expect(matrixFiles.has('test/skill-e2e-workflow.test.ts')).toBe(true);
+    expect(matrixFiles.has('test/skill-e2e-ship-docsync.test.ts')).toBe(true);
+  });
+
+  test('every matrix file exists on disk', () => {
+    const missing = [...matrixFiles.keys()].filter(
+      (f) => !fs.existsSync(path.join(ROOT, f))
+    );
+    expect(missing).toEqual([]);
+  });
+
+  test('every gate-hosting paid file is in the matrix (or the documented backlog)', () => {
+    const gaps: string[] = [];
+    for (const file of paidFiles) {
+      const source = fs.readFileSync(path.join(ROOT, file), 'utf-8');
+      const declaresGate = wholeFileTier(source) === 'gate';
+      const inGateDeps = Object.entries(E2E_TOUCHFILES).some(
+        ([key, deps]) =>
+          (E2E_TIERS as Record<string, string>)[key] === 'gate' &&
+          (deps as string[]).includes(file)
+      );
+      if (!declaresGate && !inGateDeps) continue;
+      if (matrixFiles.has(file) || KNOWN_MATRIX_GAPS.has(file)) continue;
+      gaps.push(file);
+    }
+    expect(
+      gaps,
+      `Gate-hosting test file(s) missing from the evals.yml matrix — CI will ` +
+        `never run them and "gate tier blocks merge" becomes silently false. ` +
+        `Add a matrix row (with tier: gate when the file is whole-file gated). ` +
+        `Do NOT extend KNOWN_MATRIX_GAPS for new files.`
+    ).toEqual([]);
+  });
+
+  test('matrix rows for whole-file-gated files carry a matching tier property', () => {
+    const mismatches: string[] = [];
+    for (const [file, row] of matrixFiles) {
+      if (!fs.existsSync(path.join(ROOT, file))) continue;
+      const declared = wholeFileTier(fs.readFileSync(path.join(ROOT, file), 'utf-8'));
+      if (!declared) continue;
+      if (row.tier === declared) continue;
+      if (KNOWN_TIER_UNSET.get(file) === declared && row.tier === undefined) continue;
+      mismatches.push(`${file} declares '${declared}' but row '${row.name}' has tier: ${row.tier ?? 'unset'}`);
+    }
+    expect(
+      mismatches,
+      `A whole-file tier guard with no matching row tier means the suite ` +
+        `self-skips and the CI job reports a hollow green. Set tier: <declared> ` +
+        `on the row (the Run step exports it as EVALS_TIER).`
+    ).toEqual([]);
+  });
+
+  test('burn-down lists hold only live gaps (ratchet cleanup enforcement)', () => {
+    const staleGaps = [...KNOWN_MATRIX_GAPS].filter(
+      (f) => matrixFiles.has(f) || !fs.existsSync(path.join(ROOT, f))
+    );
+    expect(
+      staleGaps,
+      'Entry fixed or file removed — delete it from KNOWN_MATRIX_GAPS.'
+    ).toEqual([]);
+    const staleTiers = [...KNOWN_TIER_UNSET.entries()].filter(([f, declared]) => {
+      const row = matrixFiles.get(f);
+      if (!row) return true; // row deleted — entry no longer applies
+      if (row.tier === declared) return true; // fixed — entry must go
+      if (!fs.existsSync(path.join(ROOT, f))) return true;
+      return wholeFileTier(fs.readFileSync(path.join(ROOT, f), 'utf-8')) !== declared;
+    });
+    expect(
+      staleTiers.map(([f]) => f),
+      'Entry fixed, row removed, or guard changed — delete it from KNOWN_TIER_UNSET.'
+    ).toEqual([]);
+  });
+});