Credit the user who forked a task as a co-author on its merge

internal/store/store.go

@@ -795,7 +795,7 @@ func (s *Store) Participants(ctx context.Context, taskID string) ([]api.Particip
 	rows, err := s.db.QueryContext(ctx, `
 		SELECT u.login, u.display_name, u.git_name, u.git_email
 		FROM events e JOIN users u ON u.login = e.actor
-		WHERE e.task_id = ? AND e.kind = 'user.message'
+		WHERE e.task_id = ? AND (e.kind = 'user.message' OR (e.kind = 'task.created' AND json_extract(e.payload, '$.forked_from') IS NOT NULL))
 		GROUP BY u.login ORDER BY min(e.seq)
 	`, taskID)
 	if err != nil {