Personal bot that syncs two Google accounts (work + personal) into
SQLite once a day and sends Telegram reminders before events.

- Google OAuth (calendar.readonly) with CSRF-checked state; paste-URL
  fallback for servers without a public callback
- Daily cron sync + /sync; recurring instances expanded by Google;
  updates, cancellations and reschedules handled
- Notification worker reads only the local DB; SentNotifications
  prevents duplicates across restarts
- /today: Google-Calendar-style day image (SkiaSharp) with join links,
  meeting links extracted from location/description
- Docker Compose deployment, EF Core migrations, 31 unit tests

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>