[FEATURE REQUEST] Add Group Message Read Receipt Functionality #3527

Why this feature?

I would like to propose adding a group message read receipt functionality to OpenIM. This feature would allow users to see who has read specific messages in group chats, similar to what's available in popular messaging apps like Dingtalk.

Currently, OpenIM supports read receipts for individual conversations, but in group chats, users can only see their own read status without knowing which group members have read specific messages.

Suggested Solution

1. Message Read Status Tracking: Track which users have read each message in group chats
2. Read User List: Display a list of users who have read a specific message
3. Read Statistics: Show read count vs total group member count for each message
4. Real-time Updates: Provide real-time notifications when users read messages

Additional Information

No response