Customer automation needs to know which conversations still need an agent's attention. The REST API already supports `notificationsUnread` on GET /tickets, but the MCP `find_tickets` tool has no unread filter and its list summaries omit the `notificationsUnread` flag (only `get_ticket` returns it). Request: add a `notificationsUnread` filter parameter to MCP `find_tickets` and include the flag in list summaries.