feat(admin): 密码校验统一与后台 API/设置增强

- 管理端账号/代理/站点等密码最短长度统一为 6 位
- LotterySettings、审计日志展示、币种与报表接口等小修复
- 补充设置批量更新、注单、校验错误等相关测试

app/Http/Controllers/Api/V1/Admin/Currency/AdminCurrencyStoreController.php

@@ -24,7 +24,7 @@ final class AdminCurrencyStoreController extends Controller
             $currency = Currency::query()->create([
                 'code' => $data['code'],
                 'name' => $data['name'],
-                'decimal_places' => (int) ($data['decimal_places'] ?? 2),
+                'decimal_places' => 2,
                 'is_enabled' => $enabled,
                 'is_bettable' => $bettable,
             ]);