[Task] New Grpah-UI(hubble) backend module issues

## Description (Suitable for newcomers)

Compile and verify the new Hubble frontend + backend modules based on PR #632, resolve runtime issues, and ensure the new graph backend is accessible. (based on the code → 1.7.0)

## Background

PR https://github.com/apache/incubator-hugegraph-toolchain/pull/632 introduced changes to the Hubble codebase. This task aims to validate those changes by building and running the updated system.

## Tasks

### 1. Build Verification
- [ ] Compile the new Hubble frontend & BE module (refer README/doc)

### 2. Runtime Issue Resolution
- [ ] Identify existing runtime bugs in the backend
- [ ] Fix minor bugs that prevent normal operation
- [ ] Verify all fixes with appropriate testing (Better, at least with the doc)

### 3. End-to-End Validation
- [ ] Start the backend service successfully
- [ ] Access the new graph backend through the frontend
- [ ] Confirm the full functionality of the integrated system (GraphServer + GraphLoader)

## Success Criteria

- ✅ Both frontend and backend compile without errors
- ✅ Backend starts and runs without critical errors
- ✅ Frontend can successfully connect to and interact with the backend
- ✅ New graph backend is fully accessible and operational

## References

- PR: https://github.com/hugegraph/hugegraph-toolchain/pull/4
- PR: https://github.com/apache/hugegraph-toolchain/pull/632 (legacy)

## Notes

Focus on resolving blockers that prevent the new graph backend from being accessible. Document any workarounds or configuration changes required.

Start with the Hubble README or documentation and the changes from PR #632. Build the frontend and backend, then run the integrated system around GraphServer and GraphLoader to identify runtime blockers. Done means both modules compile, the backend starts, and the frontend connects to and uses the new graph backend; document any workarounds or configuration changes.

Written by the indexing model from the issue text.