WinRacing V52.3 — False Positive / False Negative Analyzer

Added:
- FP/FN root-cause classification
- Error category, severity, diagnostic context and correction suggestion per race
- Aggregated error count, share, priority score and affected race list
- Error Pattern Ranking ordered by priority
- Dashboard FP/FN command panel and root-cause cards
- API payload error_analysis section

Safety:
- Advisory only
- No live weight change
- No V44-V51 score or decision change
- No database schema mutation
