Support tickets

Backed by tickets.py (the smallest controller — 282 lines). All routes require auth.

GET /api/tickets

List the caller’s tenant’s support tickets.

POST /api/tickets/create

{
  "subject": "Instance won't start",
  "description": "Getting a 502 after the last restart.",
  "priority": "high"
}

GET /api/tickets/<id>

Single ticket detail, including its reply thread.

POST /api/tickets/<id>/reply

{ "message": "Any update on this?" }

Appends a reply to the ticket thread.