- Add user metrics to mana-core-auth MetricsService:
- auth_users_total: Total registered users
- auth_users_verified: Email-verified users
- auth_users_created_today/this_week/this_month
- Create Grafana user-statistics dashboard with:
- User overview stats (total, verified, verification rate, new today)
- Registration period breakdown (today/week/month)
- User growth trends over time
- Enhance telegram-stats-bot /users command:
- Add yesterday comparison with trends
- Add week-over-week comparison
- Add mini bar chart for last 7 days registration
- Include user stats in daily Telegram report
