Remove empty-state helper copy from Home search and keep result-state behavior

[Copilot]

Home search currently shows an instructional placeholder under the search bar before any query is entered, which adds visual noise without improving usability. This change removes that pre-query helper text while preserving existing search result and no-result behaviors.

• Search empty-state behavior

  • Removed rendering of the "Start typing to search tutorials, examples, and projects." message when searchQuery is empty.
  • Empty query state now renders no extra content beneath the search input.

• Results / no-results behavior preserved

  • Non-empty query + matches: results grid renders as before.
  • Non-empty query + no matches: existing "No search results found." message remains unchanged.

• Render logic cleanup

  • Extracted search results branch into a searchResultsContent variable to keep JSX conditional flow straightforward.

const searchResultsContent = hasSearchQuery
    ? searchResults.length
        ? searchResults.map(/* existing card rendering */)
        : <p className="ui grey inverted segment">{lf("No search results found.")}</p>
    : null;