test: delete test-infrastructure dead code (G)

- exit-propagation drives the runner's real strict verdict
  (BunTestOutputClassifier + strictTestExitCode); delete the unused
  shardRunLooksTruncated predicate.
- delete skill-coverage-matrix registry + its gate (nothing reads it; the
  floor already iterates skillCensus()).
- delete touchfiles-facade export-parity tests (Bun fails missing imports
  at link time) and the duplicated E2E_TIERS tier-value test.
- delete brain-cache-spec TRANSPORT_DEFAULT_POLICY, SKILL_RUN_RETENTION_DAYS
  and the now-unused BrainTrustPolicy type with their literal tests.
  AUTOPLAN_PREFLIGHT_BUDGET_BYTES stays: skill-preflight-budget enforces it
  against real resolver output.
- delete audit-compliance's JSDoc-comment grep.

test/audit-compliance.test.ts

@@ -118,12 +118,6 @@ describe('Audit compliance', () => {
   });
 
   // Fix 5: Data flow documentation in review.ts
-  test('review.ts has data flow documentation', () => {
-    const review = readFileSync(join(ROOT, 'scripts/resolvers/review.ts'), 'utf-8');
-    expect(review).toContain('Data sent');
-    expect(review).toContain('Data NOT sent');
-  });
-
   // Round 2 Fix 3: Extension sender validation + message type allowlist
   test('extension background.js validates message sender', () => {
     const bg = readFileSync(join(ROOT, 'extension/background.js'), 'utf-8');