test: copy carved sections into all e2e fixtures (prevent more carve-blind CI fails)

Proactive sweep beyond the two CI logs: every e2e test that copies a carved
skill's SKILL.md into a temp fixture must also copy its sections/, or the
model hits a STOP pointing at a missing section file and improvises/degrades.

- skill-e2e.test.ts: plan-ceo/plan-eng/plan-design/office-hours copies across
  planDir/reviewDir/ohDir/benefitsDir dests now copy sections/.
- skill-e2e-plan.test.ts: the office-hours copy + the 4-skill codex-offering
  loop now copy sections/.
- skill-e2e-design.test.ts: plan-design-review copy now copies sections/.
- skill-e2e-office-hours.test.ts: both office-hours copies now copy sections/.
- skill-e2e-office-hours-brain-writeback.test.ts: GBRAIN_SAVE_RESULTS moved into
  the section, so check the regenerated skeleton+section UNION for the gbrain put
  block, ship both into the workdir, and restore both (the section regen was also
  leaking into the working tree — finally now restores it).

ship copies (single-file Step-0 slices) and review/retro (not carved) untouched.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

test/skill-e2e-design.test.ts

@@ -326,6 +326,7 @@ describeIfSelected('Plan Design Review E2E', ['plan-design-review-plan-mode', 'p
       path.join(ROOT, 'plan-design-review', 'SKILL.md'),
       path.join(dir, 'plan-design-review', 'SKILL.md'),
     );
+    { const _sec = path.join(ROOT, 'plan-design-review', 'sections'); if (fs.existsSync(_sec)) fs.cpSync(_sec, path.join(dir, 'plan-design-review', 'sections'), { recursive: true }); }
 
     return dir;
   }