Remove PROCESSED_FILE references and update .env.example with placeholder
Uptime URLs for privacy.
Changes:
- Remove unused processed_file variable and loading in main.py
- Update .env.example to use generic Uptime URLs
- Remove processed_uids.txt from .gitignore
Add core IMAP forwarding logic with time-based searches and Message-ID
deduplication to prevent duplicates in destination mailbox.
Changes:
- Implement SINCE-based email search using last_run.txt for incremental forwarding
- Add Message-ID extraction and IMAP checks for deduplication
- Configure systemd user services with drop-in overrides for portability
- Integrate Uptime Kuma pings for monitoring
- Set up virtual environment for dependency isolation
- Update documentation and configuration templates
