gates: close the audit findings — enforce the gates the docs claimed

An adversarial audit found the enforcement story ahead of the code: gates
that were documented as hard gates were advisory, manual, or absent, and
several human-facing claims outran the machine record. This makes the
claims true.

High findings

- Differential fuzz was documentation, not enforcement: verdict hardcoded
  fuzz_iters=0 and diff-test hardcoded the gate to Skipped, while the case
  studies claimed 10k-iteration fuzz on the same wins. Fuzz is now a real
  pipeline gate (strict FUZZ-RESULT contract, executed count recorded), and
  it is inherently baseline-vs-candidate, so it runs on the accept path and
  reports Skipped in the standalone `just gates` flow. New hard rule: a
  machine `accepted` verdict is impossible unless the fuzz gate actually
  passed — otherwise it caps at needs-human-review.
- The agent's system prompt claimed FP/concurrency/unsafe patches were
  "routed to human review automatically". No such mechanism existed. Added
  a conservative lexical risk classifier (crates/verdict/src/risk.rs) that
  forces needs-human-review on any would-be accept carrying those signals;
  fp-tolerance equivalence always signals.
- The local verdict path ran agent-influenced code unsandboxed. It now runs
  under scripts/no-net.sh (network namespace) and fails closed. Upstream
  test suites are hash-verified against corpora/<t>/TESTSUITE.sha256 when
  present (scripts/pin-testsuite.sh generates them).

Also fixed, found while fixing the above

- The pipeline script's `set -e` was inert (brace group as the left operand
  of `&&`), so a failing candidate build did not abort the run and verdict
  could bench a stale binary. Now a scoped subshell whose status is branched
  on at top level.
- A wrapper that exits before exec'ing (no-net.sh refusing, bad wrapper path)
  stranded RUNNING.lock and left read_verdict polling forever. Failure
  accounting now lives outside the wrapper.
- harnessd's patch allowlist ignored git rename/copy headers and --no-prefix
  diffs; the rename-escape case is now a committed regression test.
- The workspace did not compile on Windows (ungated Unix APIs). cfg-gated;
  71 portable tests now run on both platforms.
- pin-check regenerated the corpus manifest instead of verifying it; it is
  now verify-only, with a deliberate `just pin-corpus` to re-pin.
- Max RSS is captured per run on Unix; PMU counters are opt-in diagnostics
  (compare --perf-stat), never part of the accept decision.

Docs now match the code, including what is NOT yet enforced: no target ships
a TESTSUITE.sha256 pin, no target declares [build].tsan, and matmul is not
wired to the fp-tolerance gate — each is stated as mechanized-but-inert
rather than done. Corrected the stale "33 ledger rows" (34), the playbook's
class-3 cJSON win (rejected), adversarial-review.md's sanitizer-separation
claim (five accepted rows carry sanitizers_clean=false), the unsupported
"40,000 requests" figure, and the blanket "historical rows record
fuzz_iters=0" (8 of 10; phase0-tokei-002/-003 record 4,332).

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

results/adversarial-review.md

@@ -57,3 +57,19 @@ consistent, with the compound tokei figure stated as an approximation
   the case study and is now enforced by the report generator too.
 - `phase0-comrak-002` (mimalloc) is `needs-human-review`, awaiting a ruling
   (see `results/rulings/`).
+
+## Erratum (2026-07-13)
+
+Finding 1's separation claim above — "only the historical overturned row
+is `accepted + false`, so the rule cleanly separates them" — was too
+strong. **Five** accepted rows carry `sanitizers_clean: false`:
+`phase1-verdict-smoke-002`, `phase1-ipc-smoke-001`, `phase2-tokei-001`,
+`phase2-tokei-003`, and `phase2-comrak-010`. All five pre-date the
+machine-enforced sanitizer lane — the Phase 1 rows are harness smoke
+tests, and the two Phase 2 tokei wins were sanitizer-audited by hand
+during the 100% Phase 2 audit (see the Phase 2 case study) — but the
+ledger's machine record cannot distinguish "manually audited clean" from
+"never run", so the report generator's not-shippable rule flags all five,
+not just the overturned row. That is the correct conservative behavior;
+only the description of *why* the rule separates cleanly was wrong. The
+original text stands unedited above; this note is the correction.