feat(UI): Add the search query to the response.

Also, tweaked the search retriever prompt so it gives better search queries.

src/components/MessageBox.tsx

@@ -278,6 +278,12 @@ const MessageBox = ({
                     Sources
                   </h3>
                 </div>
+                {message.searchQuery && (
+                  <div className="mb-2 text-sm bg-light-secondary dark:bg-dark-secondary rounded-lg p-3">
+                    <span className="font-medium text-black/70 dark:text-white/70">Search query:</span>{' '}
+                    <span className="text-black dark:text-white">{message.searchQuery}</span>
+                  </div>
+                )}
                 <MessageSources sources={message.sources} />
               </div>
             )}