[Feature] Add /traversers/sameneighborsbatch API endpoint to support client-side batch same neighbors queries

### Feature Description (功能描述)

## Background
When running the SameNeighborsBatchApiTest in the [hugegraph-client]project, all related test cases fail with HTTP 404 errors. Manual curl requests to /graphs/hugegraph/traversers/sameneighborsbatch also return 404.

*After discovering reports, logs and codebases. Here's what I would like to propose.*

Before submit

- [x] 我已经确认现有的 [Issues](https://github.com/apache/hugegraph/issues?q=sort%3Aupdated-desc+is%3Aissue+is%3Aopen) 与 [FAQ](https://hugegraph.apache.org/docs/guides/faq/) 中没有相同 / 重复问题 (I have confirmed and searched that there are no similar problems in the historical issue and documents)

## Problem
The **SameNeighborsBatchApiTest** is not included in the client's Maven test suite, so this issue was not previously detected in CI.
The server does not implement the /traversers/sameneighborsbatch API endpoint, which is required by the client.

## Proposal
Please add the /traversers/sameneighborsbatch API endpoint to hugegraph-server to support batch same neighbors queries, so that the client-side tests can pass.

## Reference
(https://github.com/apache/incubator-hugegraph-toolchain/blob/master/hugegraph-client/src/test/java/org/apache/hugegraph/api/traverser/SameNeighborsBatchApiTest.java)