Enhance Discord bot status automation

[demassimo]

Summary

• replace the Discord bot text status with an auto-updating embed, smarter presence strings, and slash commands for channel setup and player lookups
• extend both database backends to store the status message identifier and provide player search helpers consumed by the bot
• preserve the stored status message when updating Discord integration settings through the API

Testing

• node --check backend/src/discord-bot-service.js

---

https://chatgpt.com/codex/tasks/task_e_68d70a1ad45c83319793ed0180fcd823