fix(services): forbid deleting service items/sections — deactivate only

Services are referenced by appointments, sessions, invoices and payment history,
so deleting one orphans/corrupts those records (deleting a section cascaded to
its services too). Make deletion impossible:

- Backend: DELETE /service-item/{uuid} and DELETE /service-section/{uuid} now
  always return 409 (ERR_SERVICE_ITEM_IN_USE) with a message pointing to
  deactivate; no rows are touched. Deactivate stays via PATCH active=false.
- Frontend: removed the section delete button, its confirm dialog, the delete
  mutation, and the now-unused delete state/flag/icon from ClinicServicesPage.
  Section and item deactivate toggles are unchanged.

Tests: ServiceItemDeleteCleanupTest rewritten — delete of item and section both
rejected (409) and the row survives. docs/api/clinic-services.md updated.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

assets/admin/pages/ClinicServicesPage.tsx

@@ -2,7 +2,7 @@ import React, { useState } from 'react';
 import { useNavigate } from 'react-router-dom';
 import { useQuery, useMutation, useQueryClient } from '@tanstack/react-query';
 import {
-  PlusIcon, PencilIcon, TrashIcon, WrenchScrewdriverIcon, BanknotesIcon,
+  PlusIcon, PencilIcon, WrenchScrewdriverIcon, BanknotesIcon,
   ShieldCheckIcon, MagnifyingGlassIcon, EyeIcon, EyeSlashIcon,
   EllipsisHorizontalIcon, CheckCircleIcon, XCircleIcon, ChevronRightIcon,
   XMarkIcon, UsersIcon, ClockIcon,
@@ -48,12 +48,10 @@ function ClinicServicesPageInner() {
   const { can } = usePermissions();
   const canCreate = can('services', 'create');
   const canUpdate = can('services', 'update');
-  const canDelete = can('services', 'delete');
   const navigate = useNavigate();
 
   const [selectedSection, setSelectedSection] = useState<ServiceSection | null>(null);
   const [sectionModal, setSectionModal] = useState<'create' | ServiceSection | null>(null);
-  const [deleteSection, setDeleteSection] = useState<ServiceSection | null>(null);
   const [itemModal, setItemModal] = useState<'create' | ServiceItem | null>(null);
   const [toggleItem, setToggleItem] = useState<ServiceItem | null>(null);
   const [tariffItem, setTariffItem] = useState<ServiceItem | null>(null);
@@ -98,17 +96,6 @@ function ClinicServicesPageInner() {
     onError: (e: any) => toast.error(e.message),
   });
 
-  const delSection = useMutation({
-    mutationFn: (uuid: string) => api.delete(`/api/v1/service-section/${uuid}`),
-    onSuccess: () => {
-      qc.invalidateQueries({ queryKey: ['service-sections'] });
-      if (selectedSection?.uuid === deleteSection?.uuid) setSelectedSection(null);
-      setDeleteSection(null);
-      toast.success('بخش حذف شد');
-    },
-    onError: (e: any) => { toast.error(e.message); setDeleteSection(null); },
-  });
-
   const toggleSection = useMutation({
     mutationFn: ({ uuid, active }: { uuid: string; active: boolean }) =>
       api.patch(`/api/v1/service-section/${uuid}`, { active }),
@@ -188,18 +175,11 @@ function ClinicServicesPageInner() {
                     </span>
                   </div>
 
-                  {(canUpdate || canDelete) && (
+                  {canUpdate && (
                     <div style={{ display: 'flex', gap: 6, borderTop: '1px solid var(--border)', paddingTop: 10, marginTop: 8 }} onClick={(e) => e.stopPropagation()}>
-                      {canUpdate && (
-                        <button className="btn sm ghost" aria-label="ویرایش" style={{ display: 'flex', alignItems: 'center', gap: 4, color: 'var(--text-2)' }} onClick={() => openEditSection(s)}>
-                          <PencilIcon style={{ width: 15 }} />
-                        </button>
-                      )}
-                      {canDelete && (
-                        <button className="btn sm ghost" aria-label="حذف" style={{ display: 'flex', alignItems: 'center', gap: 4, color: 'var(--danger)' }} onClick={() => setDeleteSection(s)}>
-                          <TrashIcon style={{ width: 15 }} />
-                        </button>
-                      )}
+                      <button className="btn sm ghost" aria-label="ویرایش" style={{ display: 'flex', alignItems: 'center', gap: 4, color: 'var(--text-2)' }} onClick={() => openEditSection(s)}>
+                        <PencilIcon style={{ width: 15 }} />
+                      </button>
                     </div>
                   )}
                 </div>
@@ -385,17 +365,6 @@ function ClinicServicesPageInner() {
 
       <ServiceInsuranceModal item={insuranceItem} onClose={() => setInsuranceItem(null)} />
 
-      {/* Confirm حذف بخش */}
-      <ConfirmDialog
-        open={!!deleteSection}
-        title="حذف بخش"
-        message={`آیا مطمئن هستید که می‌خواهید بخش «${deleteSection?.name}» و همه‌ی سرویس‌های آن را حذف کنید؟`}
-        confirmLabel="حذف"
-        onConfirm={() => deleteSection && delSection.mutate(deleteSection.uuid)}
-        onCancel={() => setDeleteSection(null)}
-        loading={delSection.isPending}
-      />
-
       {/* Confirm فعال/غیرفعال سرویس */}
       <ConfirmDialog
         open={!!toggleItem}