按MaiBot官方消息结构修复群聊被识别为私聊

变更项：\n1. outbound message_info 从旧 sender_info/receiver_info 改为官方 BaseMessageInfo 顶层字段：user_info + group_info。\n2. 群聊消息携带 group_info，私聊消息不携带 group_info，避免服务端按私聊兜底路由。\n3. 调整 _resolve_reply_route：优先解析官方新结构，保留对历史 sender_info/receiver_info 回包的兼容。\n4. 增补中文注释，说明协议字段语义与兼容策略，便于后续排障与升级。

plugins/maibot_adapter/main.py

@@ -518,32 +518,22 @@ class MaiBotAdapterPlugin(MessagePluginInterface):
             f"sender={sender}, message_id={message_id}"
         )
 
-        sender_info: Dict[str, Any] = {
-            "user_info": {
-                "platform": self._platform_name,
-                "user_id": sender,
-                "user_nickname": sender_name,
-            }
+        # 按 MaiBot 官方 BaseMessageInfo 结构组装：
+        # 1. user_info：消息“发送者”的用户信息（群聊/私聊都必须存在）；
+        # 2. group_info：仅群聊存在，私聊应为 None/缺省；
+        # 3. 不再发送 sender_info/receiver_info 这套旧字段，避免服务端按私聊路径兜底解析。
+        user_info: Dict[str, Any] = {
+            "platform": self._platform_name,
+            "user_id": sender,
+            "user_nickname": sender_name,
         }
-        receiver_info: Dict[str, Any] = {}
-
+        group_info: Optional[Dict[str, Any]] = None
         if roomid:
-            receiver_info["group_info"] = {
+            group_info = {
                 "platform": self._platform_name,
                 "group_id": roomid,
                 "group_name": group_name,
             }
-            # 群聊场景只保留 group_info，不再混入 receiver.user_info：
-            # 1. sender 身份已经通过 sender_info.user_info 完整表达；
-            # 2. 若群聊再附带 receiver.user_info，部分下游会优先按“用户会话”归类；
-            # 3. 这正是你目前看到“群消息被显示成私聊”的高概率根因。
-            # 4. 因此这里明确约束：群聊 receiver 只承载群维度路由信息。
-        else:
-            receiver_info["user_info"] = {
-                "platform": self._platform_name,
-                "user_id": sender,
-                "user_nickname": sender_name,
-            }
 
         api_message = {
             "message_info": {
@@ -563,8 +553,8 @@ class MaiBotAdapterPlugin(MessagePluginInterface):
                     "abot_route_type": route_type,
                     "abot_route_source": route_source,
                 },
-                "sender_info": sender_info,
-                "receiver_info": receiver_info,
+                "user_info": user_info,
+                "group_info": group_info,
             },
             "message_segment": {
                 "type": "text",
@@ -636,9 +626,31 @@ class MaiBotAdapterPlugin(MessagePluginInterface):
 
     def _resolve_reply_route(self, message_info: Dict[str, Any]) -> Optional[Dict[str, str]]:
         """从 MaiBot 返回的 message_info 中解析微信路由。"""
+        # 优先按官方当前结构解析：
+        # 1. group_info 存在 => 群回复；
+        # 2. user_info 存在 => 私聊回复。
+        root_group_info = message_info.get("group_info") or {}
+        root_user_info = message_info.get("user_info") or {}
+        group_id = str(root_group_info.get("group_id", "") or "").strip()
+        root_user_id = str(root_user_info.get("user_id", "") or "").strip()
+
+        if group_id:
+            return {
+                "route_type": "group",
+                "target": group_id,
+                "at_target": root_user_id,
+            }
+
+        if root_user_id:
+            return {
+                "route_type": "private",
+                "target": root_user_id,
+                "at_target": "",
+            }
+
+        # 兼容历史 sender_info/receiver_info 结构，避免升级期间回包偶发失配。
         receiver_info = message_info.get("receiver_info") or {}
         sender_info = message_info.get("sender_info") or {}
-
         receiver_group_info = receiver_info.get("group_info") or {}
         receiver_user_info = receiver_info.get("user_info") or {}
         sender_user_info = sender_info.get("user_info") or {}