[Feature] Improve Search Experience: Show 'No Results Found' When Query Yields No Matches

## Problem
When a user performs a search in search-index.html, there is no feedback or message displayed if no items match the search query. This can lead to confusion for users, as they might not realize that the search did not yield any results.

## Description
A "No results found" message should be displayed when a search query returns no matches. This feature will provide clear feedback to users, improving the search experience by ensuring that users know when their search did not find any results.

## Alternatives
An alternative could be to clear the search results area when no matches are found, but this approach might not provide as much clarity to the user. Showing a "No results found" message is a more user-friendly solution, as it explicitly informs the user of the search outcome.

## Implementation

- [ ] I would be interested in implementing this feature.