Add three new endpoints under /integrations/psa:
- GET /tickets/search: search CW tickets with query, board_id, status_id filters
- GET /tickets/{ticket_id}: fetch a single ticket by ID
- GET /tickets/{ticket_id}/statuses: get available statuses for a ticket's board
Add PSATicketSearchResult and PSATicketStatusItem schemas.
All endpoints require engineer_or_admin auth.
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>