feat: Wahab demo prep — Cancelled status, phone persistence, admin delete, users picker, detail-page fixes

- Add Cancelled as terminal status reachable from all active states; exclude
  from SLA breach reporting and dashboard active counts; add to status pickers
- Persist customer phone on ticket create/update (was silently dropped);
  add tickets.phone migration + legacy self-heal guard
- Add admin-only DELETE /api/tickets/{id} (removes timeline/photos/escalations)
- Add GET /api/auth/users for the assign-technician dropdown (was hardcoded)
- TicketOut now returns nested unit/category so the detail page stops showing
  '—' for Unit/Property/Category
- Ticket numbering uses max+1 so deletions never re-issue a number
- New-issue form: require Category and (standard mode) Priority client-side
- Tests: 11 new cases covering cancellation, SLA exemption, phone, delete,
  users endpoint, numbering

AGENTS.md

@@ -52,6 +52,7 @@ Users, units, and categories are auto-seeded on first startup via lifespan hook:
 | POST | `/api/auth/refresh` | Token | Refresh tokens |
 | GET | `/api/auth/me` | Bearer | Current user |
 | GET | `/api/auth/admin-only` | Admin/Jerome, Admin/Wahab | RBAC demo endpoint |
+| GET | `/api/auth/users` | Bearer | List users (id, name, role) for the assign-technician picker |
 | POST | `/api/whatsapp/mock` | No | Mock WhatsApp |
 | GET | `/api/whatsapp/mock-log` | No | Recent mock submissions |
 
@@ -75,6 +76,7 @@ Frontend: Alpine.js (CDN) + Tailwind CSS (CDN). Auth state in localStorage. Role
 | GET | `/api/tickets` | No | List tickets (filter: status, priority, property, building, unit_id, category_id, assigned_to, date_from, date_to) |
 | GET | `/api/tickets/{id}` | No | Get ticket detail with timeline, photos, SLA status |
 | PATCH | `/api/tickets/{id}` | Bearer | Update ticket (validates status transitions) |
+| DELETE | `/api/tickets/{id}` | Admin/Jerome, Admin/Wahab | Delete ticket + children (timeline/photos/escalations); test/scratch cleanup only |
 | POST | `/api/tickets/{id}/status` | Bearer | Change status with note |
 | GET | `/api/tickets/{id}/sla` | No | Check SLA breach status |
 | POST | `/api/tickets/{id}/photos` | Bearer | Upload photos (multipart, is_before param) |
@@ -91,8 +93,11 @@ Frontend: Alpine.js (CDN) + Tailwind CSS (CDN). Auth state in localStorage. Role
 
 ## Ticket System (Sprint 2)
 
-### Status Lifecycle (15 statuses)
-New → Logged → Triage → Assigned → Accepted → Travelling → On Site → In Progress → Waiting Parts → Escalated → Completed → On-Field Verification → Wahab Review → Closed → Reopened
+### Status Lifecycle (16 statuses)
+New → Logged → Triage → Assigned → Accepted → Travelling → On Site → In Progress → Waiting Parts → Escalated → Completed → On-Field Verification → Wahab Review → Closed → Reopened → Cancelled
+
+Cancelled is terminal (no outgoing transitions) and reachable from any active
+state; it is excluded from SLA breach reporting and dashboard "active" counts.
 
 Valid transitions defined in `app/services/ticket.py::VALID_TRANSITIONS`. Invalid transitions return 400.