fix: my chat member

handlers/group_handlers.py

@@ -65,9 +65,13 @@ def register_group_handlers(bot: telebot.TeleBot) -> None:
                     db.close()
                 break
     
-    @bot.chat_member_handler()
+    # NOTE:
+    # Updates about the bot itself (когда бота повышают до админа / понижают)
+    # приходят в поле `my_chat_member`, а не `chat_member`.
+    # Для их обработки в pyTelegramBotAPI нужно использовать my_chat_member_handler.
+    @bot.my_chat_member_handler()
     def handle_chat_member_update(message: telebot.types.ChatMemberUpdated) -> None:
-        """Handle chat member updates (including bot becoming admin)."""
+        """Handle my_chat_member updates (bot role changes, e.g. becoming admin)."""
         bot_me = bot.get_me()
         if not bot_me:
             return