Site Search: new pattern

A wrapper around combobox and autocomplete with more context around a site's main search box.

https://playbook.ebay.com/design-system/components/search-bar

<img width="908" alt="Image" src="https://github.com/user-attachments/assets/7ac8cf05-1cd8-4e25-971d-ef2928b0077d" />