refactor(modmail): centralize config into single /modmail config panel

- Remove 5 redundant commands (setup, addcategory, removecategory, enable, disable)
- Single /modmail config opens interactive Components V2 panel
- Channel select for ticket category, role select for staff, channel select for logs
- Toggle enable/disable button
- Categories sub-panel: add via modal, remove via select
- Fix lint (unused imports/vars, contextlib.suppress) + ruff format

vision.py

@@ -2,8 +2,6 @@ import asyncio
 import logging
 import sys
 
-from dotenv import load_dotenv
-
 import config
 from bot import VisionBot