- Add real-time progress bar with updates every 500 msgs / 5 sec
- Fix Telegram rate limiting: batch=25, delay=1.0s (~25 msg/sec)
- Add global flood_wait_until to prevent semaphore slot starvation
- Add parse_mode=HTML for web API broadcasts
- Separate error handling for FloodWait, Forbidden, BadRequest
- Convert ORM objects to scalars before long broadcast operations
- Add email recipients dataclass to prevent detached ORM state