fix(wallet-service): remove invalid nested $queryRaw in getOfflineSettlementSummary

删除使用嵌套 $queryRaw 进行条件拼接的错误查询，保留简化版本。

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

backend/services/wallet-service/src/application/services/wallet-application.service.ts

@@ -3012,25 +3012,7 @@ export class WalletApplicationService {
       : 0;
     const totalCount = aggregateResult._count.id || 0;
 
-    // 查询按月统计
-    const monthlyStats = await this.prisma.$queryRaw<Array<{
-      month: string;
-      amount: any;
-      count: any;
-    }>>`
-      SELECT
-        TO_CHAR(created_at, 'YYYY-MM') as month,
-        SUM(deducted_amount) as amount,
-        COUNT(*) as count
-      FROM offline_settlement_deductions
-      ${params.startDate ? this.prisma.$queryRaw`WHERE created_at >= ${params.startDate}` : this.prisma.$queryRaw``}
-      ${params.endDate ? this.prisma.$queryRaw`AND created_at <= ${params.endDate}` : this.prisma.$queryRaw``}
-      GROUP BY TO_CHAR(created_at, 'YYYY-MM')
-      ORDER BY month DESC
-      LIMIT 12
-    `;
-
-    // 简化查询：不使用条件拼接
+    // 查询按月统计（简化版本，不使用日期筛选）
     const byMonth = await this.prisma.$queryRaw<Array<{
       month: string;
       amount: any;