fix(chat): restore history on Turnstile verification

Turnstile callback unconditionally showed the greeting message, wiping
session history for returning visitors who hadn't verified yet.

Callback now uses the same restoreOrGreet pattern as neuronDemoToggle:
replays prior messages if session.messages is non-empty, else shows the
greeting once and marks session.greeted.

Also extracts the gallery voting inline script (a49ca0a129e8.js) as a
side effect of re-running extract-js.py. Chat JS rebuilds to de72b8b61d75.js.

src/styles.el

@@ -2023,7 +2023,7 @@ fn page_close() -> String {
   </div>
 </div>
 
-<script src=\"/assets/js/37b5ead0d425.js\" defer></script>
+<script src=\"/assets/js/de72b8b61d75.js\" defer></script>
 </body>
 </html>
 "