fix(ui): show the search filters only while a search runs

The filter row of the chat search showed from the first typed character,
when a search has not started yet, so a change of a filter did nothing.
It now shows from two characters, or while a filter is on.

Assisted-by: Claude:claude-sonnet-5-5

core/http/react-ui/src/components/ChatsList.jsx

@@ -188,7 +188,7 @@ export default function ChatsList({
   }
 
   const listId = `${idPrefix}-menu-list`
-  const showFilters = Boolean(onSearch) && search.trim().length > 0
+  const showFilters = searching || (Boolean(onSearch) && filtersActive(filters) && search.trim().length > 0)
   const meta = searching && found.status === 'ready' ? found.meta : null
 
   // The words under the list while a search runs or ends.