Telegram userbot relay that monitors specified group chats and forwards
bot messages to OpenClaw's inject-http endpoint via webhook.
Features:
- GramJS (MTProto) for reading bot messages (invisible to Bot API)
- Media download + multipart form upload
- BOT_EXCLUDE filter (by user ID or @username)
- HTML entity formatting (bold, italic, code, pre, links, etc.)
- Graceful shutdown on SIGINT/SIGTERM
- .env configuration with validation
