fix: close the gaps the review of the trial-5 fixes found

- park-attempt-files: parks in the git dir (outside the work tree, so Sub-step C.2 never registers a parked file again), reads a path with a space, names a new file under a header it cannot read, parks a symlink, never overwrites a parked file, and exits 1 while a file the attempt made is still in the tree; the upward diff is saved in one form whatever the git config.

- brief-validator: BRIEF_SC_NOT_RUNNABLE only when a later backticked span is a command; a criterion that only names a flag or a path stays prose (Handover 1 says so now).

- review ids: counted over the final list (runContract), as fill-finding-ids counts review.md; trimmed_count matches rows by id; engine-findings and fidelity-diff use computeFindingIds; the --workflow dedup keeps one source's different findings apart, the decision-23 put-back stays one copy per triplet.

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

tests/scripts/trekreview-armb-workflow.test.mjs

@@ -627,3 +627,13 @@ test('decision 23 — Handover 6 states the dedup rank on both paths, the put-ba
   assert.match(h6, PUT_BACK);
   assert.match(h6, FLOOR_B);
 });
+
+test('armB — two different /code-review findings on one triplet stay two rows for the coordinator (trial 5, finding 7)', async () => {
+  const c = await floorCase({
+    codeFindings: [F('CODE_REVIEW_DEFECT', 'MAJOR', { title: 'EAGAIN on stdin' }), F('CODE_REVIEW_DEFECT', 'MAJOR', { title: 'A lone CR does not split lines' })],
+    reviewerFindings: [F('CODE_REVIEW_DEFECT', 'MAJOR', { title: 'EAGAIN on stdin' })],
+    returned: [F('CODE_REVIEW_DEFECT', 'MAJOR')],
+    verdict: 'WARN',
+  });
+  assert.deepEqual(c.merged.map((f) => f.title).sort(), ['A lone CR does not split lines', 'EAGAIN on stdin']);
+});