feat(trekplan): Regression and On failure step rules, and trial 2's minor fixes

The minor points (B8-B12, C13, C14, C16, C17) of the second voyage-lekerepo
trial (2026-10-08), each verified against the code and started with a test
that failed first.

- K10: optional step field `Regression:` - one command the criteria runner
  allows, unpiped; plan-validator refuses one that can never run
  (PLAN_STEP_REGRESSION_NOT_RUNNABLE). Any plan_version, no bump.
- K11: `On failure:` opens with revert | retry | skip | escalate, or the
  validator warns (PLAN_STEP_ON_FAILURE_UNKNOWN); onFailureAction in
  plan-schema.
- B8 (operator decision 2026-10-08): minors open after the last critic round
  are listed numbered in the Phase 10 summary; the ones the operator picks are
  fixed and get one more round (--extra-round when the 3 are spent).
- B11: plan-review dedup merges two reviewers' findings on the same file:line
  with the same content (trial pair: Jaccard 0.44, overlap 0.83); the Jaccard
  threshold for every other pair is unchanged.
- B12: /trekbrief Step 4c says the reviewer runs in the background and is
  waited for, not "foreground, blocking".
- C13: the Phase 4 size count includes .mjs, .cjs, .mts, .cts.
- C14: --evidence shows the first output line on PASS rows.
- C16: findings-schema checks path:line citations in finding prose (error) and
  in the prose around the block (warning) against the file.
- C17: git-historian gets the brief, never proposes changing a frozen file,
  and names the remote from `git remote -v`.

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

lib/verification/criteria-runner.mjs

@@ -610,7 +610,10 @@ export function formatCriteriaEvidence(rep) {
     for (const r of rep.results) {
       const cmd = r.command ? `\`${cell(r.command)}\`` : '(none)';
       const exit = r.exitCode === null ? '—' : `exit ${r.exitCode}`;
-      const evidence = r.status === 'passed' ? '—' : cell(firstLine(r.output)) || '—';
+      // The first line of output on every row, a PASS too: /trekreview tells
+      // the reviewer it gets "the command, exit code and first line of output",
+      // and a PASS row said "—" (voyage-lekerepo trial 2, 2026-10-08).
+      const evidence = cell(firstLine(r.output)) || '—';
       out.push(`| ${r.label} | ${cmd} | ${MARK[r.status]} | ${exit} | ${evidence} |`);
     }
     const s = rep.summary;