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/AdminUserUpdateRequest.php

@@ -34,7 +34,7 @@ final class AdminUserUpdateRequest extends ApiFormRequest
         return [
             'nickname' => ['sometimes', 'string', 'max:128'],
             'email' => ['sometimes', 'nullable', 'string', 'email', 'max:255', Rule::unique('admin_users', 'email')->ignore($adminUser?->id)],
-            'password' => ['sometimes', 'nullable', 'string', 'min:8', 'max:256'],
+            'password' => ['sometimes', 'nullable', 'string', 'min:6', 'max:256'],
             'status' => ['sometimes', 'integer', Rule::in([0, 1])],
         ];
     }