IAV-540/add ticket management module with CRUD, assignment, and integration support
- Add TicketService with create, read, update, assign, and status/priority management
- Add TicketRepository with filtered queries, open ticket checks, and collaborator lookup
- Add TicketController with REST endpoints for full ticket lifecycle
- Add TicketMapper for entity-DTO conversion with N8N response support
- Add TicketPaths with centralized path constants
- Add DTOs: TicketCreateRequestDTO, TicketResponseDTO, TicketN8nResponse, OpenTicketResult
Closes IAV-540