`cmdRoadmapUpdatePlanProgress` only marked phase-level checkboxes
(e.g. `- [ ] Phase 50: Build`) but skipped plan-level entries
(e.g. `- [ ] 50-01-PLAN.md`). Now iterates phase summaries and
marks matching plan checkboxes as complete.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>