IAV-1266/feat(sav): wire conversation title update and harden ticket chat thread
- Add updateConversationTitle to customer-care agent conversation API, config endpoints, and conversation store.
- ticket-detail: normalize ticket conversation payloads, sort by time, stable row keys (createdAt/uid), dedupe optimistic sends after real messages.
- Broaden conversation/sender typing (CLIENT vs CUSTOMER, optional uid) and align use-agent-chat / ticket types with backend DTOs.