[BUG] duplicated on_message handler

**Describe the bug**
event.py and nqn.py both used `on_message` event handler, however discord.py only allow one of them

**Expected behavior**
A global handler should be used to broadcast the event to other module

**Screenshots**

<img width="309" height="188" alt="Image" src="https://github.com/user-attachments/assets/c6e36b4d-91f4-4b73-acf6-bfeadc112e1e" />
