Add support for environment variables for Docker and automation compatibility

[sherlock7402]

This PR improves automation compatibility by introducing support for environment variables, making the bot easier to use in Docker containers or other non-interactive environments (e.g. cronjobs). Suggestion in Discord: https://discord.com/channels/1302750463904579665/1353538974970544208

Changes:

• AUTO_UPDATE environment variable added:
  • AUTO_UPDATE=true → automatically applies updates without user input.
  • AUTO_UPDATE=false → skips updates silently.
  • Not set → falls back to interactive prompt as before.
  • Clear console messages indicate how AUTO_UPDATE is interpreted.
• BOT_TOKEN can now be provided via environment (BOT_TOKEN=...) instead of always requiring bot_token.txt or user input.
• Behavior remains backward compatible for local/interactively run scripts.
• Docker support example added in docker-compose.yaml:

Benefits:

• Compatible with Docker, systemd, and crontab jobs.
• Avoids blocking prompts in automated setups.
• Easier installation