fix(mining-admin-service): 修复 manual-mining 分页参数 NaN 问题

NestJS transform 会将缺失的 query 参数转为 NaN,
而 NaN ?? 1 仍然是 NaN。改用 Number(page) || 1 确保默认值生效。

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

backend/services/mining-admin-service/src/api/controllers/manual-mining.controller.ts

@@ -99,7 +99,7 @@ export class ManualMiningController {
     @Query('page') page?: number,
     @Query('pageSize') pageSize?: number,
   ) {
-    return this.manualMiningService.getRecords(page ?? 1, pageSize ?? 20);
+    return this.manualMiningService.getRecords(Number(page) || 1, Number(pageSize) || 20);
   }
 
   @Get('records/:accountSequence')