feat: port payment management tab from tauri to admin dashboard

Add per-clinic payment methods (bank accounts + POS/card-reader devices)
under the "مدیریت پرداخت" settings tab at /admin/my-financial, ported from
clinic-pro-tauri's mock-only PaymentManagement tab into a real persisted
feature. These records are referenceable (by uuid) from patient invoices to
record which method a service payment was made with.

Backend (new src/PaymentMethod domain):
- BankAccount + Pos entities, repositories, PaymentMethodService (validation,
  ownership scoping, create/update/toggle logic).
- Thin PaymentMethodController exposing /api/v1/my/payment-methods/{bank-accounts,pos}
  (GET/POST/PUT + PATCH .../status), guarded to clinic/doctor/secretary/admin.
- Migration for bank_accounts + pos_devices tables.
- Functional tests (success + validation/404/403 + empty boundaries).
- docs/api/payment-method.md.

Frontend:
- Replace MyFinancialPage content with the payment-management UI (two tabs,
  tables, add/edit modals, status toggle) using the admin design system.
- usePaymentMethods hook (TanStack Query) + presentational components.
- Update page test to cover tabs, data, empty state and the add modal.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

assets/admin/components/paymentMethods/PosFormModal.tsx

@@ -0,0 +1,97 @@
+import React, { useEffect, useState } from 'react';
+import { toast } from 'sonner';
+import Modal from '../ui/Modal';
+import SearchableSelect from '../ui/SearchableSelect';
+import { BANK_OPTIONS } from './banks';
+import {
+  useCreatePos,
+  useUpdatePos,
+  type Pos,
+} from '../../hooks/usePaymentMethods';
+
+/**
+ * فرم افزودن/ویرایش کارت‌خوان — پورت مبدأ ModalAddPose.jsx.
+ * اگر `pos` داده شود حالت ویرایش، وگرنه افزودن.
+ */
+export default function PosFormModal({
+  open,
+  pos,
+  onClose,
+}: {
+  open: boolean;
+  pos: Pos | null;
+  onClose: () => void;
+}) {
+  const isEdit = !!pos;
+  const [bankName, setBankName] = useState('');
+  const [terminalNumber, setTerminalNumber] = useState('');
+  const [accountNumber, setAccountNumber] = useState('');
+
+  const createMut = useCreatePos();
+  const updateMut = useUpdatePos();
+  const pending = createMut.isPending || updateMut.isPending;
+
+  useEffect(() => {
+    if (!open) return;
+    setBankName(pos?.bank_name ?? '');
+    setTerminalNumber(pos?.terminal_number ?? '');
+    setAccountNumber(pos?.account_number ?? '');
+  }, [open, pos]);
+
+  const submit = () => {
+    if (!bankName.trim()) { toast.error('نام بانک الزامی است'); return; }
+    if (!terminalNumber.trim()) { toast.error('شماره ترمینال الزامی است'); return; }
+
+    const body = {
+      bank_name: bankName.trim(),
+      terminal_number: terminalNumber.trim(),
+      account_number: accountNumber.trim(),
+    };
+
+    const onSuccess = () => {
+      toast.success(isEdit ? 'کارت خوان ویرایش شد' : 'کارت خوان اضافه شد');
+      onClose();
+    };
+    const onError = (e: unknown) => toast.error(e instanceof Error ? e.message : 'خطا در ذخیره');
+
+    if (isEdit && pos) {
+      updateMut.mutate({ uuid: pos.uuid, body }, { onSuccess, onError });
+    } else {
+      createMut.mutate(body, { onSuccess, onError });
+    }
+  };
+
+  return (
+    <Modal
+      open={open}
+      onClose={onClose}
+      title={isEdit ? 'ویرایش کارت خوان' : 'افزودن کارت خوان'}
+      size="sm"
+      footer={
+        <button className="btn primary" style={{ width: '100%' }} disabled={pending} onClick={submit}>
+          {pending ? '...' : isEdit ? 'ذخیره تغییرات' : 'اضافه کردن کارت خوان'}
+        </button>
+      }
+    >
+      <div style={{ display: 'flex', flexDirection: 'column', gap: 16 }}>
+        <div>
+          <label className="field-label">نام بانک</label>
+          <SearchableSelect
+            options={BANK_OPTIONS}
+            value={bankName || null}
+            onChange={(v) => setBankName(v != null ? String(v) : '')}
+            placeholder="انتخاب بانک"
+          />
+        </div>
+        <div>
+          <label className="field-label">شماره ترمینال</label>
+          <input className="input" value={terminalNumber} onChange={(e) => setTerminalNumber(e.target.value)} placeholder="شماره ترمینال" />
+        </div>
+        <div>
+          <label className="field-label">شماره حساب</label>
+          <input className="input" value={accountNumber} onChange={(e) => setAccountNumber(e.target.value)} placeholder="شماره حساب" />
+        </div>
+      </div>
+    </Modal>
+  );
+}