- Add `custom_bot_manager.py` for core bot lifecycle management.
- Introduce new API endpoints for custom bot status, start, stop, restart, and log retrieval.
- Extend `UserSettings` and `GlobalSettings` models with custom bot configuration options (token, enabled, prefix, status).
- Create a dedicated "Custom Bot" page in the dashboard (`custom-bot.html`) with associated JavaScript to configure settings and control the bot.
- Integrate custom bot initialization into the application startup.
