Add beginner-friendly automated test coverage

## Goal
Add focused automated tests for one small, well-isolated OpenOrbit feature.

## Suggested scope
Choose one API or UI behavior that currently has limited coverage, then add a clear success case and one meaningful failure or edge case. Good candidates include asset deletion safeguards, telemetry trace shaping, or empty-state behavior.

## Acceptance criteria
- Tests are deterministic and do not require external credentials or network access.
- The test names explain the expected behavior.
- `PYTHONPATH=backend pytest -q` passes.
- Briefly document the chosen coverage in the pull request.