fix(server): improve message handling and data privacy

- fix unread count calculation logic in message repository
- implement logic to retrieve other participant's last read sequence in conversation handlers
- mask real names in verification record responses for privacy
- improve error reporting in main entry point by using stderr instead of zap logger during initialization

internal/repository/message_repo.go

@@ -896,10 +896,11 @@ func (r *messageRepository) GetUnreadCountBatch(ctx context.Context, userID stri
 	}
 	var rows []row
 	err := r.db.WithContext(ctx).
-		Table("conversation_participants cp").
-		Select("cp.conversation_id, COALESCE(cnt.unread, 0) as count").
-		Joins("LEFT JOIN (SELECT m.conversation_id, COUNT(m.id) as unread FROM messages m WHERE m.sender_id <> ? AND m.deleted_at IS NULL AND m.conversation_id IN (?) GROUP BY m.conversation_id) cnt ON cnt.conversation_id = cp.conversation_id AND cnt.unread > cp.last_read_seq", userID, convIDs).
-		Where("cp.user_id = ? AND cp.conversation_id IN (?)", userID, convIDs).
+		Table("messages m").
+		Select("m.conversation_id, COUNT(m.id) as count").
+		Joins("JOIN conversation_participants cp ON cp.conversation_id = m.conversation_id AND cp.user_id = ?", userID).
+		Where("m.sender_id <> ? AND m.deleted_at IS NULL AND m.seq > cp.last_read_seq AND m.conversation_id IN (?)", userID, convIDs).
+		Group("m.conversation_id").
 		Scan(&rows).Error
 	if err != nil {
 		return nil, err