- Add API Key caching (5min) to reduce D1 queries
- Remove updateApiKeyLastUsed to reduce unnecessary writes
- Extend stats API cache from 30s to 5min
- Fix SiteStats growth rate calculation (total vs daily)
- Fix deploy.yml to handle empty PASSWORD and API_RATE_LIMIT_PER_MINUTE
- Add emails index (message_to, created_at) for faster queries
- Implement lightweight /api/emails/meta for smart polling
- Reduce frontend polling: check meta every 60s, fetch full list only on change