docs(client): fix notifications.list README example to use real read option (#7194)

The README's only usage example for client.notifications.list showed
{ unreadOnly: true }, a key the implementation has never read. The real
options are { read?, type?, limit? }; replace the example with
{ read: false } (the semantic equivalent of unread-only).

Fixes #6927

Co-authored-by: Claude <noreply@anthropic.com>

Author: os-help

packages/client/README.md

@@ -256,7 +256,7 @@ await client.approvals.approve(requestId, 'LGTM');
 await client.approvals.reject(requestId, 'Incomplete');
 
 // Notifications
-await client.notifications.list({ unreadOnly: true });
+await client.notifications.list({ read: false }); // unread only
 await client.notifications.markRead(['notif-1', 'notif-2']);
 
 // AI Services