Fix root path_segments handling in resource tree right pane

[souvikDevloper]

Issues

• Closes: #

Changes

• add test coverage for resource tree right-pane navigation context
• add coverage for root path, nested path breadcrumb context, and top-level directory context
• fix path_segments generation for the root path so it does not produce an empty breadcrumb segment

While exploring the current tree/codebase navigation flow, I noticed that the right-pane context-building logic produced an empty breadcrumb segment for the root path. I fixed that behavior and added tests to make the expected navigation context explicit.

Checklist

• I have read the contributing guidelines
• I have linked an existing issue above
• I have added unit tests covering the new code
• I have reviewed and understood every line of this PR

[souvikDevloper]

I checked the failing CI job, and the failure appears to be in scanpipe.tests.test_pipelines during pipeline result fixture comparison, while this PR only changes scanpipe/views.py and scanpipe/tests/test_views.py. I also verified scanpipe.tests.test_views locally with SQLite and it passes. This looks unrelated to the resource-tree change, but I’m happy to investigate further if maintainers think there’s a connection.

[tdruez]

https://github.com/aboutcode-org/scancode.io/blob/main/CONTRIBUTING.md#pull-request-rules

Attach your PR to an existing issue. Discuss the approach and implementation details in the issue first, before writing any code. Please note that if the issue has already been assigned to someone else, you are welcome to comment on it, but it would be best to contribute code in such a case only if you are invited to do so.