fix(bot): normalize mention case for command handling

Ensure that the bot commands are recognized regardless of the letter casing of the mention. This improves command compatibility and user experience by allowing flexibility in how the bot is invoked. Prior to this change, commands were case-sensitive, potentially leading to inconsistencies in command recognition.

src/matrix_applicationbot/classes/bot.py

@@ -64,7 +64,7 @@ class ApplicationBot:
         body = event.body if hasattr(event, "body") else None
 
         if body:
-            mention = body.split()[0]
+            mention = body.split()[0].lower()
             if mention == "!applicationbot" or mention in self.username:
                 return await self.handle_command(room, sender, body.split(" ", 1)[1])