feat(tickets): add tickets API client, update integrations API for paginated search, fix callers

- Create frontend/src/api/tickets.ts with ticketsApi (resources, status, create, ai-parse, priorities, search)
- Update integrationsApi.searchTickets and searchTicketsQueue return types from PSATicketSearchResult[] to TicketListResponse
- Fix TicketQueue.tsx to use results.items (append/set) and results.items.length for pagination check
- Fix TicketPickerModal.tsx to use results.items when setting search results
- Export ticketsApi from api/index.ts

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

frontend/src/api/index.ts

@@ -37,3 +37,4 @@ export { handoffsApi } from './handoffs'
 export { resolutionsApi } from './resolutions'
 export { deviceTypesApi } from './deviceTypes'
 export { networkDiagramsApi } from './networkDiagrams'
+export { ticketsApi } from './tickets'