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.
Will Anderson
4c5d4b3c84