fix(chat): do not respond with llm in private messages

bot.py

@@ -109,6 +109,13 @@ class Bot:
     if not content:
       return
     
+    # Do not respond with llm in private messages
+    if isinstance(message.channel, discord.DMChannel):
+      response = DiscordResponse(message)
+      await response.write(message, 'I am sorry, I am unable to respond in private messages.')
+      return
+    
+    # Admin commands
     if content == 'RESET' and str(message.author.id) == self.admin_id:
       await self.flush_channel(str(message.channel.id))
       logging.info('Chat reset by admin in guild %s', message.channel.guild.name)