fix: round 7 of the release review of 6.3.0, for 6.3.1

Round 7 (516dffa..45aa9e1, WARN: 12 MAJOR, 0 BLOCKER) and the fence defect
found while writing its review.md. Each fix began with a test that failed on
0f400d3 (v6.3.0); suite 2208 (2206/0/2), 14 tests more.

- Tests-only (operator 2026-10-11): the plan's Files: alone decides, and the
  text says so (red-proof, trekexecute Sub-step B, step-implementer,
  HANDOVER-CONTRACTS). red-proof no longer reads the step's diff, so a change
  already in the tree when the step began no longer counts against it, and a
  plan placed outside .claude/ reads the same. The round-6 test that had the
  diff overrule the plan is rewritten to the new rule.
- The Files: reader keeps a plain file beside a backticked path
  (", Dockerfile", "the CLI entry src/cli.mjs", "and Makefile"). Measured on
  the 520 Files: fields in 182 plans: no field reads differently.
- Red proof reports a command its timeout killed as killed after the timeout,
  not "could not start"; the release check tells a timeout from output past
  its buffer and from another signal. One reading of a stop
  (criteria-runner stoppedBy) for red proof, the criteria runner and the
  release check.
- A trailing `# comment` is dropped in a backticked check too, and in a
  command passed as written, so the words screened are the words run.
- The release check reads a relative --review in --repo.
- The 15-minute timeout is defined once (criteria-runner.mjs).
- The findings check reads each cited file once per validation.
- One isMain helper (lib/util/is-main.mjs) for every CLI: the 31 copies of
  the realpath guard and the 20 modules still on the file:// guard, which
  exited 0 having done nothing under a symlink or a path with a space.
- The Bash guard writes its no-one-to-ask refusal once, on a direct condition.
- The findings check ends a ```json block only at a fence on its own line, so
  three backticks inside a JSON string no longer end it (also in 6.2.0).
- Brief-conformance notes: a test for test-lock green on exit 127 (it
  passed at once; it fails when 127 is read as could-not-run); the prose now
  names the git revision `@~1` as the one leading-@ exception.

Not changed: the example plan's steps 1-2 keep their tests-only warning
(operator decision 2026-10-09; the r5 test records it). Brief note 4 (a
Regression: whose runner is not installed goes to the fix rounds) is a
routing question for the operator.

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

docs/HANDOVER-CONTRACTS.md

@@ -269,7 +269,7 @@ prose form (relaxed in S26 so the template's prose emission parses).
 7. **Every plan_version, no version bump** (a plan without the field validates unchanged; voyage-lekerepo trial 2, 2026-10-08):
    - **K10 — `Regression:`** (optional step field): ONE backticked command the criteria runner's allowlist runs, with no pipe and no `&&` (first backticked span, as for `Verify:`). The executor runs it green before the step's checkpoint; a step without it runs nothing new. `Verify:` stays the step's own red-first test. One that can never run is `PLAN_STEP_REGRESSION_NOT_RUNNABLE` (an error; a warning under `--soft`).
    - **K11 — `On failure:`** opens with one of `revert`, `retry`, `skip`, `escalate` (case-insensitive; a leading `**`, `_`, backtick or `-` is ignored, other leading characters are not; `onFailureAction` in `lib/parsers/plan-schema.mjs`), the words `/trekexecute` reads; any other opening is the warning `PLAN_STEP_ON_FAILURE_UNKNOWN`. A missing `On failure:` is unchanged (the executor defaults to `escalate`).
-   - **A step of only tests** (order 10, voyage-lekerepo trial 3, 2026-10-09): when every file in a step's `Files:` is a test (its `Test first:` file, or a path `lib/util/test-path.mjs` reads as a test: under `tests/`, `test/`, `__tests__/`, `spec/`, `specs/`, or named `*.test.*`, `*.spec.*`, `*_test.*`, `*_spec.*`, `test_*.py`, but never a document such as `docs/specs/api.md`; `stepTestsOnly` in `lib/parsers/plan-schema.mjs`), the warning is `PLAN_STEP_TESTS_ONLY`: the behaviour its tests cover exists at its start point, so it can never be proven red. A step without `Files:` is not judged. At run time `red-proof.mjs --plan <plan.md> --step <N>` puts the same reading on a `not-red-at-base` as `tests_only`, true only when every file the step changed since its start point is a test too, and `/trekexecute` sends a `tests_only: true` step straight up to the plan.
+   - **A step of only tests** (order 10, voyage-lekerepo trial 3, 2026-10-09): when every file in a step's `Files:` is a test (its `Test first:` file, or a path `lib/util/test-path.mjs` reads as a test: under `tests/`, `test/`, `__tests__/`, `spec/`, `specs/`, or named `*.test.*`, `*.spec.*`, `*_test.*`, `*_spec.*`, `test_*.py`, but never a document such as `docs/specs/api.md`; `stepTestsOnly` in `lib/parsers/plan-schema.mjs`), the warning is `PLAN_STEP_TESTS_ONLY`: the behaviour its tests cover exists at its start point, so it can never be proven red. A step without `Files:` is not judged. At run time `red-proof.mjs --plan <plan.md> --step <N>` puts the same reading on a `not-red-at-base` as `tests_only`: the plan's `Files:` alone decides, and the step's diff is not read (operator 2026-10-11), and `/trekexecute` sends a `tests_only: true` step straight up to the plan.
 
 **Validation strategy:**