tighten xiaoniu reply triggers for direct mentions only

plugins/ai_auto_response/main.py

@@ -124,6 +124,8 @@ class AIAutoResponsePlugin(MessagePluginInterface):
             return False
         if self._should_ignore(content):
             return False
+        if self._is_targeting_other_user(message):
+            return False
         return True
 
     async def process_message(self, message: Dict[str, Any]) -> Tuple[bool, Optional[str]]:
@@ -299,6 +301,12 @@ class AIAutoResponsePlugin(MessagePluginInterface):
             return True
         return any(content.startswith(prefix) for prefix in self.filters.get("ignore_prefixes", []))
 
+    def _is_targeting_other_user(self, message: Dict[str, Any]) -> bool:
+        if message.get("is_at", False):
+            return False
+        raw_content = str(message.get("content", "") or "")
+        return "@" in raw_content
+
     def _get_sender_name(self, room_id: str, sender: str) -> str:
         try:
             members = ContactManager.get_instance().get_group_members(room_id)