[Cleanup] Remove dead TabNav component if unused

[realproject7]

Problem

PR #215 replaced the sort tabs on the home page with a dropdown (SortDropdown using Select). The TabNav component may now be dead code if nothing else imports it.

Fix

1. Search codebase for any remaining imports of TabNav
2. If unused, delete the component file
3. If still used elsewhere, leave it

Acceptance Criteria

• No dead component files in the repo