refactor(plan-eng-review): carve review body into on-demand section

Fourth Phase B carve (v2_PLAN.md:220). Moves the 4-section review (Architecture,
Code Quality, Tests, Performance), outside voice, required outputs, and review
report — everything after Step 0 scope — into sections/review-sections.md behind
a single STOP-Read. Step 0 (scope challenge) and EXIT_PLAN_MODE_GATE stay in the
always-loaded skeleton.

Measured: skeleton 106,984 -> 54,892 B (-48.7%). Union preserved. Atomic with
tests + all-host regen (freshness gate): parity flipped to sectioned
(maxSkeletonBytes 62K), plan-eng-review added to SECTIONS_EXTRACTED, gen-skill-docs
reads the union for relocated review/TEST_COVERAGE/dashboard prose. Layer 0 green.

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

test/gen-skill-docs.test.ts

@@ -383,7 +383,7 @@ describe('gen-skill-docs', () => {
   });
 
   test('voice and writing-style preamble sections stay compact', () => {
-    const content = fs.readFileSync(path.join(ROOT, 'plan-eng-review', 'SKILL.md'), 'utf-8');
+    const content = readSkillUnion('plan-eng-review'); // carved: review body moved to section
     const voice = extractMarkdownSection(content, '## Voice');
     const writingStyle = extractMarkdownSection(content, '## Writing Style');
 
@@ -392,7 +392,7 @@ describe('gen-skill-docs', () => {
   });
 
   test('slim voice section preserves the gstack voice contract', () => {
-    const content = fs.readFileSync(path.join(ROOT, 'plan-eng-review', 'SKILL.md'), 'utf-8');
+    const content = readSkillUnion('plan-eng-review'); // carved: review body moved to section
     const voice = extractMarkdownSection(content, '## Voice');
 
     expect(voice).toMatch(/lead with the point|direct/i);
@@ -693,7 +693,7 @@ describe('REVIEW_DASHBOARD resolver', () => {
   });
 
   test('shared dashboard propagates review source to plan-eng-review', () => {
-    const content = fs.readFileSync(path.join(ROOT, 'plan-eng-review', 'SKILL.md'), 'utf-8');
+    const content = readSkillUnion('plan-eng-review'); // carved: review body moved to section
     expect(content).toContain('plan-eng-review, review, plan-design-review');
     expect(content).toContain('`review` (diff-scoped pre-landing review)');
   });
@@ -739,7 +739,7 @@ describe('REVIEW_DASHBOARD resolver', () => {
   });
 
   test('plan-eng-review chaining mentions design and ceo reviews', () => {
-    const content = fs.readFileSync(path.join(ROOT, 'plan-eng-review', 'SKILL.md'), 'utf-8');
+    const content = readSkillUnion('plan-eng-review'); // carved: review body moved to section
     expect(content).toContain('/plan-design-review');
     expect(content).toContain('/plan-ceo-review');
   });
@@ -761,7 +761,7 @@ describe('REVIEW_DASHBOARD resolver', () => {
 // ─── Test Coverage Audit Resolver Tests ─────────────────────
 
 describe('TEST_COVERAGE_AUDIT placeholders', () => {
-  const planSkill = fs.readFileSync(path.join(ROOT, 'plan-eng-review', 'SKILL.md'), 'utf-8');
+  const planSkill = readSkillUnion('plan-eng-review'); // carved
   const shipSkill = readShipUnion();
   const reviewSkill = fs.readFileSync(path.join(ROOT, 'review', 'SKILL.md'), 'utf-8');
 
@@ -1369,7 +1369,7 @@ describe('Codex filesystem boundary', () => {
 
 describe('BENEFITS_FROM resolver', () => {
   const ceoContent = fs.readFileSync(path.join(ROOT, 'plan-ceo-review', 'SKILL.md'), 'utf-8');
-  const engContent = fs.readFileSync(path.join(ROOT, 'plan-eng-review', 'SKILL.md'), 'utf-8');
+  const engContent = readSkillUnion('plan-eng-review'); // carved
 
   test('plan-ceo-review contains prerequisite skill offer', () => {
     expect(ceoContent).toContain('Prerequisite Skill Offer');
@@ -2649,7 +2649,7 @@ describe('community fixes wave', () => {
 
   // #510 — Context warnings: plan-eng-review has explicit anti-warning
   test('plan-eng-review/SKILL.md contains "Do not preemptively warn"', () => {
-    const content = fs.readFileSync(path.join(ROOT, 'plan-eng-review', 'SKILL.md'), 'utf-8');
+    const content = readSkillUnion('plan-eng-review'); // carved: review body moved to section
     expect(content).toContain('Do not preemptively warn');
   });
 

test/helpers/parity-harness.ts

@@ -245,7 +245,13 @@ export const PARITY_INVARIANTS: ParityInvariant[] = [
     minBytes: 80_000,
   },
   {
+    // Carved (v2 plan T9): skeleton + sections/review-sections.md. The 4-section
+    // review, outside voice, and required outputs moved to the section; content
+    // checks run against the union. Skeleton shrank 106,984 -> 54,892 B (-48.7%);
+    // maxSkeletonBytes 62KB = measured + headroom.
     skill: 'plan-eng-review',
+    sectioned: true,
+    maxSkeletonBytes: 62_000,
     mustContain: [
       'Architecture',
       'Code Quality',

test/skill-size-budget.test.ts

@@ -163,7 +163,7 @@ describe('SKILL.md size budget regression (gate, free)', () => {
     // because prose moved into sections/*.md. The union size is guarded instead
     // by the sectioned ship invariant in parity-harness.ts (minBytes on the
     // skeleton+sections union), so exempt the skeleton from the body-strip floor.
-    const SECTIONS_EXTRACTED = new Set<string>(['ship', 'plan-ceo-review', 'office-hours']);
+    const SECTIONS_EXTRACTED = new Set<string>(['ship', 'plan-ceo-review', 'office-hours', 'plan-eng-review']);
 
     const undershoots: Array<{
       skill: string; beforeBytes: number; afterBytes: number; ratio: number;