fix: use task work order data in service report context

Ensure /putni-nalozi/racuni reads service-report context from the selected task's own work order instead of reusing the parent page work-order data for every task.

- task-service-context now returns task_work_order metadata per task
- work hours modal reads location and travel data from task_work_order
- tasks without a linked work order fall back to None

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

frontend/src/components/dashboard/WorkOrderInvoicesPdfPage.jsx

@@ -554,8 +554,8 @@ export default function WorkOrderInvoicesPdfPage() {
             <TaskWorkHoursTableModal
                 open={!!editingTask}
                 task={editingTask}
-                workOrder={workOrder}
-                defaultLocation={workOrder?.location || ''}
+                workOrder={editingTask?.task_work_order ?? null}
+                defaultLocation={editingTask?.task_work_order?.location ?? ''}
                 saving={savingWorkHours}
                 onClose={() => setEditingTask(null)}
                 onSave={handleSaveWorkHoursTable}