- Add validPlanContent() helper for building valid PLAN.md fixtures - 7 tests for verify plan-structure: missing frontmatter, valid plan, missing name, missing action, wave/depends_on, checkpoint/autonomous, and file-not-found - 4 tests for verify phase-completeness: complete phase, missing summary, orphan summary, nonexistent phase - All 14 tests in verify.test.cjs pass (3 existing + 11 new)