Fix suggestion list spacing and spinner staying visible

- Wrap TextHighlight in a span to prevent mark fragments becoming
  separate flex items with gaps between them
- Reset isSearching when search is cleared below minimum length

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: dd32

build/index.js

@@ -65,6 +65,7 @@ function DirectAdd( { postId, existingIds, onAdd } ) {
 	useEffect( () => {
 		if ( search.length < 2 ) {
 			setSuggestions( [] );
+			setIsSearching( false );
 			return;
 		}
 		setIsSearching( true );
@@ -118,7 +119,7 @@ function DirectAdd( { postId, existingIds, onAdd } ) {
 										width={ 28 }
 										height={ 28 }
 									/>
-									<TextHighlight text={ user.name } highlight={ search } />
+									<span><TextHighlight text={ user.name } highlight={ search } /></span>
 								</HStack>
 								<Button
 									variant="secondary"