Documentation search cannot be opened on mobile

Description

At mobile viewport widths, the documentation search button disappears. The mobile navigation menu has no search option, leaving touch users unable to search the docs.

Steps to reproduce

1. Run the website locally and open /actors/docs/.
2. At desktop width, confirm that the Search… button opens documentation search.
3. Set the viewport to a mobile width, such as 390 px.
4. Open the mobile navigation menu and look for a search control.

Expected behavior

A mobile user can open documentation search from the header or mobile menu.

Actual behavior

The search button is absent, and the mobile menu offers no way to open search. The ⌘K / Ctrl+K shortcut requires a physical keyboard, so it is not a practical touch alternative.

Impact

Users browsing documentation on a phone must navigate pages manually to find a topic.

Technical context

The search button uses hidden md:flex, which hides it below the md breakpoint: TypesenseSearch.tsx.

The mobile navigation renders links and the docs tree but no search control: Header.tsx.

Reproduced locally at commit 6d49592 with a 390 px viewport.

Screen recording