fix(review): close the gate's fail-open paths an independent review found

An adversarial read of d88245c reproduced 15 problems; all fixed here, each
with a test that fails on the old code.

- verdict-gate: a greener verdict must be backed by the LAST fence being a
  `json` block of the right shape, with no BLOCKER in the JSON (any case),
  in `## Findings (BLOCKER)`, or a differing finding-id list; two verdict
  lines and more than one file argument are exit 2. ({}, null, lowercase
  "blocker", a trailing ```jsonc and a later json fence all gave exit 0.)
- engine-findings: a transcribed "narrower" key can no longer lower an
  engine tier; absolute paths under --repo-root match the scope; "12" lines
  parse; an empty scope is an error; out-of-scope engine findings are
  unverified (`engine:out-of-scope`) and forbid ALLOW.
- recurrence: the catch-all engine keys and keys normalised from unknown
  ones are never proposed; the same unfixed finding in two iterations is not
  a recurrence; proposals are validated before they are offered; \r/U+2028
  and damaged markers are refused; writes go through a symlinked CLAUDE.md.
  Prose points --repo at the session directory, not the git toplevel.
- Workflow substrate: engines are counted from what arrived, and the
  verdict's floor is recomputed from the coordinator's findings; now tested
  by running the script with stubbed Workflow globals. Two literal NUL bytes
  written as \u0000 (git saw the file as binary).
- Trimming keeps Pass 1's "Also flagged by" provenance; `## Declined to
  Judge` and remediation steps are required from review_version 1.1 only
  (N-1); the zero-diff review now carries the JSON block the gate needs.

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

agents/review-coordinator.md

@@ -54,6 +54,10 @@ You will receive a prompt containing:
 - **Expected reviewers** — the names that were due, engines included, and
   each engine recorded as not run with its reason. A name that did not report
   forbids `ALLOW` (Pass 4).
+- **Engine findings outside the review scope** — the `out_of_scope` list from
+  `lib/review/engine-findings.mjs`. Each one is `unverified`
+  (`engine:out-of-scope`): a real claim on a file this review did not cover.
+  List it under `## Declined to Judge`; it forbids `ALLOW`.
 - **Triage map** — `{file → deep-review|summary-only|skip, reason}` from
   the /trekreview triage gate.
 - **Brief metadata** — `task`, `slug`, `project_dir`, `brief_path` from