feat: 수수료 갭 보완 4종 — 지급보류/환수원천세역분개/연체이자/간이지급명세서 (V124~V126)

감사(서브에이전트 3영역)로 발견한 실제 결함/규제 갭만 선별 보완.

- A 지급보류(HOLD) 지급배치 누락 버그: PaymentBatchItemMapper.insertFromSettleMaster
  status NOT IN('PAID','HOLD') — 보류건이 지급배치에 포함되어 실제 이체되던 결함 수정
- B 환수 원천세 역분개: withholding_tax_adjustment(V124) 멱등 적재 +
  분기 원천세신고 집계 netting(payment UNION ALL adjustment). settle_master 금액흐름 불변
- C 환수채권 연체이자: clawback_receivable.accrued_interest + clawback_interest(V125) +
  ClawbackInterestCalculator(연율/1200), config 기본 0 = 안전폴백, 기존 FIFO 상계가 이자 회수
- D 사업소득 간이지급명세서(월별): commission_statement(MONTHLY) 위 읽기전용 리포트 +
  메뉴 REPORT_SIMPLIFIED_PAYMENT(V126) + 프론트 SimplifiedPaymentReport

검증: ./gradlew build 전모듈 GREEN, 신규 단위테스트 6건, ga-frontend tsc -b PASS,
Flyway V124~V126 운영DB 적용(v126), 적대리뷰 APPROVED(LOW 1건 GREATEST 클램프 즉수정),
B/C/D 라이브DB 검증(롤백) + D admin e2e list/export 200.

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

ga-frontend/src/pages/commission/ClawbackReceivable.tsx

@@ -73,9 +73,16 @@ const GRID_COLS: ColDef<ClawbackReceivableRow>[] = [
     type: 'numericColumn',
     valueFormatter: (p) => fmt(p.value),
   },
+  {
+    field: 'accruedInterest',
+    headerName: '연체이자',
+    flex: 1,
+    type: 'numericColumn',
+    valueFormatter: (p) => fmt(p.value),
+  },
   {
     field: 'balance',
-    headerName: '잔액',
+    headerName: '잔액(이자포함)',
     flex: 1,
     type: 'numericColumn',
     valueFormatter: (p) => fmt(p.value),
@@ -274,7 +281,8 @@ function DrawerContent({ detail }: { detail: ClawbackReceivableDetail }) {
     { label: '발생월',    value: detail.originSettleMonth },
     { label: '발생액',    value: fmt(detail.originalAmount) },
     { label: '회수액',    value: fmt(detail.recoveredAmount) },
-    { label: '잔액',      value: fmt(detail.balance) },
+    { label: '연체이자',  value: fmt(detail.accruedInterest) },
+    { label: '잔액(이자포함)', value: fmt(detail.balance) },
     { label: '상태',      value: <StatusChip status={detail.status} statusName={detail.statusName} /> },
     { label: '최근회수월', value: detail.lastRecoveryMonth ?? '-' },
     { label: '등록일',    value: detail.createdAt ? dayjs(detail.createdAt).format('YYYY-MM-DD') : '-' },

ga-frontend/src/pages/report/SimplifiedPaymentReport.tsx

@@ -0,0 +1,108 @@
+import { useState } from 'react';
+import { Alert, DatePicker } from 'antd';
+import { ProCard, ProTable, type ProColumns } from '@ant-design/pro-components';
+import { useQuery } from '@tanstack/react-query';
+import dayjs, { type Dayjs } from 'dayjs';
+import PageContainer from '@/components/common/PageContainer';
+import MoneyText from '@/components/common/MoneyText';
+import ExcelExportButton from '@/components/common/ExcelExportButton';
+import api, { unwrap } from '@/api/request';
+
+interface SimplifiedPaymentRow {
+  agentId: number;
+  settleMonth: string;
+  agentName: string;
+  residentNo?: string;
+  businessNo?: string;
+  incomeTypeName: string;
+  grossAmount: number;
+  incomeTaxAmount: number;
+  localTaxAmount: number;
+  netAmount: number;
+}
+
+function fetchReport(settleMonth: string) {
+  return unwrap<SimplifiedPaymentRow[]>(
+    api.get('/api/report/simplified-payment', { params: { settleMonth } }),
+  );
+}
+
+const columns: ProColumns<SimplifiedPaymentRow>[] = [
+  { title: '소득자', dataIndex: 'agentName', width: 120, fixed: 'left' },
+  { title: '주민등록번호', dataIndex: 'residentNo', width: 140 },
+  { title: '사업자번호', dataIndex: 'businessNo', width: 140 },
+  { title: '소득구분', dataIndex: 'incomeTypeName', width: 90 },
+  {
+    title: '지급액', dataIndex: 'grossAmount', width: 130, align: 'right',
+    render: (_, r) => <MoneyText value={r.grossAmount} />,
+  },
+  {
+    title: '소득세', dataIndex: 'incomeTaxAmount', width: 120, align: 'right',
+    render: (_, r) => <MoneyText value={r.incomeTaxAmount} />,
+  },
+  {
+    title: '지방소득세', dataIndex: 'localTaxAmount', width: 120, align: 'right',
+    render: (_, r) => <MoneyText value={r.localTaxAmount} />,
+  },
+  {
+    title: '차인지급액', dataIndex: 'netAmount', width: 140, align: 'right',
+    render: (_, r) => <strong><MoneyText value={r.netAmount} /></strong>,
+  },
+];
+
+export default function SimplifiedPaymentReport() {
+  const [settleMonth, setSettleMonth] = useState<Dayjs>(dayjs());
+
+  const monthStr = settleMonth.format('YYYYMM');
+
+  const { data, isLoading, isError } = useQuery({
+    queryKey: ['report', 'simplified-payment', monthStr],
+    queryFn: () => fetchReport(monthStr),
+    retry: false,
+  });
+
+  return (
+    <PageContainer
+      title="사업소득 간이지급명세서"
+      description="월별 사업소득 지급·원천징수 명세 (국세청 간이지급명세서 제출 대응)"
+      extra={
+        <ExcelExportButton
+          url="/api/report/simplified-payment/export"
+          fileName={`간이지급명세서_${monthStr}`}
+          params={{ settleMonth: monthStr }}
+        />
+      }
+    >
+      {isError && (
+        <Alert
+          type="warning"
+          showIcon
+          message="조회 실패"
+          description="/api/report/simplified-payment API 응답이 없습니다."
+          style={{ marginBottom: 16 }}
+        />
+      )}
+
+      <ProCard bordered style={{ marginBottom: 16 }}>
+        <DatePicker
+          picker="month"
+          value={settleMonth}
+          onChange={(d) => d && setSettleMonth(d)}
+          allowClear={false}
+          format="YYYY-MM"
+        />
+      </ProCard>
+
+      <ProTable<SimplifiedPaymentRow>
+        rowKey="agentId"
+        columns={columns}
+        dataSource={data ?? []}
+        loading={isLoading}
+        search={false}
+        pagination={{ pageSize: 50, showTotal: (t) => `총 ${t}건` }}
+        options={{ density: false, reload: false }}
+        scroll={{ x: 1000 }}
+      />
+    </PageContainer>
+  );
+}