fix: issue invoice on demand so view-invoice buttons actually work

The admin SPA never called POST /billing/invoices, so every session had
invoice_uuid = null and the view-invoice buttons on the patient services
tab (and MyPatients visit modal) were permanently disabled. Add a shared
useIssueInvoice hook (idempotent create + finalize when draft) and wire
it into:
- DetailsStep: the wizard's final step now really issues the invoice
- SessionServiceCard / PatientDetailPage: clicking view-invoice on a
  session without an invoice issues it first, then opens the summary
- MyPatientsPage visit modal: same, replacing the dead disabled button

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

assets/admin/components/session/DetailsStep.tsx

@@ -1,12 +1,16 @@
+import { toast } from 'sonner';
 import { formatRial } from '../../lib/utils';
 import type { SessionCardData } from '../SessionServiceCard';
 import { METHOD_LABELS } from './PaymentStep';
+import { useIssueInvoice } from '../../hooks/useIssueInvoice';
 
 const primaryBtn: React.CSSProperties = { background: '#5559CE', color: '#fff', border: 'none', borderRadius: 4, height: 46, fontSize: 14, fontWeight: 500, cursor: 'pointer' };
 const ghostBtn: React.CSSProperties = { background: 'transparent', color: '#5559CE', border: '1px solid #5559CE', borderRadius: 4, height: 46, fontSize: 14, fontWeight: 500, cursor: 'pointer' };
 
 interface Props {
   session: SessionCardData;
+  /** برای invalidate شدن لیست sessions بعد از صدور فاکتور. */
+  recordUuid?: string;
   onBack: () => void;
   onFinish: () => void;
 }
@@ -15,8 +19,17 @@ interface Props {
  * گام «جزییات» — پورت tauri Step3Final با دیتای واقعی:
  * خلاصه‌ی سرویس/هزینه/تخفیف + لیست پرداخت‌شده‌ها + مانده. مشترک بین
  * NewSessionPage (ویزارد سه‌گامه) و SessionPaymentPage (دوگامه).
+ * «صدور فاکتور» فاکتور را واقعاً صادر می‌کند (create + finalize) و بعد onFinish.
  */
-export default function DetailsStep({ session, onBack, onFinish }: Props) {
+export default function DetailsStep({ session, recordUuid, onBack, onFinish }: Props) {
+  const issueMut = useIssueInvoice(recordUuid);
+  const issue = () => {
+    if (session.invoice_uuid) { onFinish(); return; }
+    issueMut.mutate(session.uuid, {
+      onSuccess: () => onFinish(),
+      onError: () => toast.error('صدور فاکتور ناموفق بود'),
+    });
+  };
   const finalPrice = session.final_price_rials ?? 0;
   const discountRials = session.discount_rials ?? 0;
   const debt = session.patient_debt_rials ?? 0;
@@ -71,7 +84,9 @@ export default function DetailsStep({ session, onBack, onFinish }: Props) {
 
       <div style={{ display: 'flex', gap: 8, marginTop: 16, width: '100%', maxWidth: 320, margin: '16px auto 0' }}>
         <button type="button" style={{ ...ghostBtn, flex: 1 }} onClick={onBack}>انصراف</button>
-        <button type="button" style={{ ...primaryBtn, flex: 1 }} onClick={onFinish}>صدور فاکتور</button>
+        <button type="button" disabled={issueMut.isPending} style={{ ...primaryBtn, flex: 1 }} onClick={issue}>
+          {issueMut.isPending ? 'در حال صدور…' : 'صدور فاکتور'}
+        </button>
       </div>
     </>
   );