fix: scope inferred work-order tasks to the current work order

Prevent service-record inference from pulling tasks from other work orders
that share the same vehicle. This keeps task-service-context, service
reports, and related work-order widgets isolated to the selected nalog.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

backend/modules/fleet/views.py

@@ -155,6 +155,7 @@ def _work_order_related_tasks_queryset(work_order):
             vehicle_id=work_order.vehicle_id,
             task_id__isnull=False,
             task__is_active=True,
+            task__work_order=work_order,
         ).values_list('task_id', flat=True)
     )
     task_ids = list({*direct_task_ids, *inferred_task_ids})