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/Requests/Admin/AdminCurrencyStoreRequest.php

@@ -17,7 +17,6 @@ final class AdminCurrencyStoreRequest extends ApiFormRequest
         return [
             'code' => ['required', 'string', 'max:16', 'regex:/^[A-Z0-9]{1,16}$/', Rule::unique('currencies', 'code')],
             'name' => ['required', 'string', 'max:64'],
-            'decimal_places' => ['sometimes', 'integer', 'min:0', 'max:12'],
             'is_enabled' => ['sometimes', 'boolean'],
             'is_bettable' => ['sometimes', 'boolean'],
         ];