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

app/routers/tickets.py

@@ -12,7 +12,7 @@ from sqlalchemy import select
 from sqlalchemy.ext.asyncio import AsyncSession
 from app.core.config import settings
 from app.core.database import get_db
-from app.core.security import get_current_user
+from app.core.security import get_current_user, require_roles
 from app.models.category import Category
 from app.models.ticket import Ticket, TicketPhoto
 from app.models.unit import Unit
@@ -250,6 +250,25 @@ async def update_ticket(
     return ticket
 
 
+@router.delete("/{ticket_id}", status_code=status.HTTP_204_NO_CONTENT)
+async def delete_ticket(
+    ticket_id: int,
+    db: Annotated[AsyncSession, Depends(get_db)],
+    current_user: Annotated[User, Depends(require_roles("Admin/Jerome", "Admin/Wahab"))],
+) -> None:
+    """Delete a ticket and its children (timeline, photos, escalations).
+
+    Admin-only: intended for removing test/scratch tickets from the demo
+    database, never for routine workflow use.
+    """
+    ticket = await ticket_service.delete_ticket(db, ticket_id)
+    # Remove orphaned photo files from disk after the DB rows are gone.
+    for photo in ticket.photos:
+        if photo.photo_url:
+            name = photo.photo_url.rsplit("/", 1)[-1]
+            (UPLOADS_DIR / name).unlink(missing_ok=True)
+
+
 # ── Status Transitions (convenience endpoints) ───────────────────────
 @router.post("/{ticket_id}/status", response_model=TicketOut)
 async def change_ticket_status(