## Summary
What does this PR change, and why?

## Related issues
Closes #

## Type of change
- [ ] Bug fix
- [ ] New feature
- [ ] Refactor / cleanup
- [ ] Documentation
- [ ] Tests

## Checklist
- [ ] `cargo build` and `cargo test` pass (client)
- [ ] `cargo fmt` and `cargo clippy` are clean
- [ ] `pytest` passes (server)
- [ ] I did not commit secrets, `.venv`, or build artifacts
- [ ] I updated docs / `CHANGELOG.md` where relevant

## Security / privacy impact
Does this affect encryption, the zero-knowledge server model, authentication,
or sandbox permissions? If so, explain. If not, write "none".

## How to test
Steps for a reviewer to verify the change.