Fixes two root causes behind bug #3517:
1. Idempotency: completed_phases was blindly incremented (parseInt + 1),
causing phase.complete N run twice to double-count (4 → 5 → 6).
Now derives from ROADMAP progress table Complete-row count, making
the operation idempotent.
2. Field coverage: eight STATE.md fields were left stale after phase
completion. Now updates in the same atomic lock section:
- frontmatter: stopped_at, last_updated, total_plans, completed_plans
- body: Current focus, Status line, By Phase table row
completed_plans = count of *-SUMMARY.md files across all phase dirs
total_plans = sum of M/N plan counts from ROADMAP progress table
percent = recomputed from fresh derived counts
Closes#3517
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
