Add pause/resume functionality for remote trading control via Telegram.
Changes:
- Add pause_trading Event to main.py
- Implement /stop handler (pause trading)
- Implement /resume handler (resume trading)
- Integrate pause logic into both daily and realtime trading loops
- Add 4 comprehensive tests for trading control
Features:
- /stop: Pauses all trading operations
- /resume: Resumes trading operations
- Idempotent: Handles repeated stop/resume gracefully
- Status feedback: Informs if already paused/active
- Works in both daily and realtime trading modes
Security:
- Commands verified by TelegramCommandHandler chat_id check
- Only authorized users can control trading
Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>