- Add /welcome command with setchannel, add, remove, list, help
- Welcome messages on guildMemberAdd event
- Goodbye messages on guildMemberRemove event
- Auto-use Discord system channel if no custom channel set
- Variables: {user}, {username}, {server}, {membercount}
- Add welcome_message and goodbye_message to guild_settings
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
