feat: improve group member events and push delivery

docs/IM-前后端对接文档.md

@@ -438,7 +438,9 @@ X-MeetingIM-APIKey: <预置的普通 API Key>
     "event": "group.member.joined",
     "payload": {
       "topic": "grp_xxx",
-      "user_id": "usr_xxx"
+      "user_id": "usr_xxx",
+      "member_sync": "single",
+      "visibility": "all_members"
     },
     "ts": "2026-08-25T10:00:00Z"
   }
@@ -456,7 +458,9 @@ X-MeetingIM-APIKey: <预置的普通 API Key>
 | 消息撤回 | Topic 在线成员 | `{"info":{"topic":"p2p_or_grp","from":"usr_actor","what":"im","event":"message.recalled","payload":{"topic":"p2p_or_grp","seq":12,"version":2}}}` | 按 `topic+seq+version` 重新拉取或本地标记已撤回 |
 | 消息编辑 | Topic 在线成员 | `{"info":{"topic":"p2p_or_grp","from":"usr_actor","what":"im","event":"message.edited","payload":{"topic":"p2p_or_grp","seq":12,"version":2}}}` | 按 `topic+seq+version` 重新拉取消息详情或修订记录 |
 | 单聊消息变更脏标记 | P2P 双方在线会话 | `{"info":{"topic":"usr_target","from":"usr_actor","what":"im","event":"message.mutation","payload":{"topic":"p2p...","seq":12,"version":2,"event":"message.recalled"}}}` | 当前未订阅该 P2P 也要标记会话脏，并调用 `message-mutations` 做补偿同步 |
-| 群业务变化 | 群 Topic 在线成员 | `{"info":{"topic":"grp...","from":"usr_actor","what":"group","event":"group.member.joined","payload":{"topic":"grp...","user_id":"usr_xxx"}}}` | 按事件刷新群详情、成员列表、入群申请、公告、禁言或角色权限；除操作人外当前会写系统通知 |
+| 成员加入 | 群 Topic 在线成员 | `{"info":{"topic":"grp...","from":"usr_actor","what":"group","event":"group.member.joined","payload":{"user_id":"usr_xxx","member_sync":"single","visibility":"all_members"}}}` | 全体成员可见；调用 `GET /v1/im/groups/{topic}/members/{user_id}` 刷新单个成员。加入事件同时写入群消息，离线后可按 Topic seq 补拉 |
+| 成员退出/移除、角色或禁言变化 | 群主、管理员和被操作人 | `{"info":{"topic":"grp...","from":"usr_actor","what":"group","event":"group.member.left","payload":{"user_id":"usr_xxx","member_sync":"remove","visibility":"admins_and_affected"}}}` | 普通成员不可见；`single` 拉取单成员，`remove` 本地删除，`full` 重新分页拉取全部成员 |
+| 其他群业务变化 | 按具体事件授权范围 | `info.what="group"` | 刷新群详情、入群申请、公告或治理权限 |
 | 会议变化 | 会议参会人 | `{"info":{"topic":"usr_target","from":"usr_actor","what":"im","event":"meeting.updated","payload":{"meeting_id":"mtg_1","version":2,"state":"scheduled"}}}` | 刷新会议列表/详情；除操作者外当前会写系统通知 |
 | 安全风险确认 | 操作人本人 | `{"info":{"topic":"usr_actor","from":"usr_actor","what":"im","event":"security.risk.continue","payload":{"risk_challenge_id":"risk_1","decision":"continue"}}}` | 刷新安全验证页面；当前会写系统通知 |
 
@@ -2173,7 +2177,8 @@ GET /v1/im/topics/{topic}/message-mutations?since_version={localMutationVersion}
 | `PATCH /v1/im/groups/{topic}/member-settings` | `{"pinned":true,"mute_notifications":false,"version":1}` | `{"topic":"grp...","pinned":true,"mute_notifications":false,"version":2,"updated_at":"2026-08-20T09:00:00Z"}` |
 | `PUT /v1/im/groups/{topic}/members/me/profile` | `{"nickname":"我在群里的昵称","version":1}` | `{"nickname":"我在群里的昵称","version":2,"updated_at":"2026-08-20T09:00:00Z"}` |
 | `POST /v1/im/groups/{topic}/leave` | `{}` | `{"topic":"grp...","status":"left"}` |
-| `GET /v1/im/groups/{topic}/members?query=&cursor=&mentionable=true` | Query only | `{"topic":"grp...","items":[{"user_id":"usr...","display_name":"张三","group_nickname":"小张","avatar_file_id":"","role":"member","mentionable":true,"acs":{"want":"JRWP","given":"JRWP","mode":"JRWP"}}],"next_cursor":"","permissions":{"can_mention_all":true}}` |
+| `GET /v1/im/groups/{topic}/members?query=&cursor=&mentionable=true` | Query only | `{"topic":"grp...","items":[{"user_id":"usr...","display_name":"张三","group_nickname":"小张","avatar_file_id":"","role":"member","member_status":"active","version":1,"joined_at":"2026-08-20T09:00:00Z","updated_at":"2026-08-20T09:00:00Z","mentionable":true,"acs":{"want":"JRWP","given":"JRWP","mode":"JRWP"}}],"next_cursor":"","sync_mode":"full","permissions":{"can_mention_all":true}}` |
+| `GET /v1/im/groups/{topic}/members/{user_id}` | Path topic/user | `{"topic":"grp...","user_id":"usr...","display_name":"张三","group_nickname":"小张","role":"member","member_status":"active","version":1,"joined_at":"2026-08-20T09:00:00Z","updated_at":"2026-08-20T09:00:00Z","sync_mode":"single","acs":{"want":"JRWP","given":"JRWP","mode":"JRWP"}}` |
 | `GET /v1/im/groups/{topic}/members/{user_id}/profile` | Path topic/user；`topic` 必须是 `grp...`，不能传 `usr...` | `{"topic":"grp...","user_id":"usr...","display_name":"张三","group_nickname":"小张","role":"member","relationship":"friend","capabilities":{"can_send":true,"can_call":true}}` |
 | `POST /v1/im/groups/{topic}/qrcodes` | `{"expires_in_seconds":86400}` | `{"qr_token":"token...","qr_payload":"im://qr?token=...&purpose=join_group","expires_at":"2026-08-21T09:00:00Z","group":{"topic":"grp...","name":"项目群","member_count":2},"group_snapshot":{"topic":"grp...","name":"项目群","member_count":2}}` |
 | `POST /v1/im/groups/{topic}/invitations` | `{"user_ids":["usr..."],"message":"进群一起讨论"}` | `{"topic":"grp...","items":[{"user_id":"usr...","status":"joined","invitation_id":"ginv_1"}]}` |