Add dismissible Weekly Huddle pop-up overlay (Sept 8)

Self-contained /announce.js injects a branded, dismissible event overlay
(the flyer + all four time zones + Join Google Meet button). Included on the
main funnel and member pages. Auto-expires after the huddle and shows once
per browser until dismissed; edit the EV block to reuse for future events.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

public/app.html

@@ -28,4 +28,5 @@
     <a class="btn btn-primary" href="/my">Open the dashboard</a>
   </div>
 </main>
-<script src="/app.js"></script></body></html>
+<script src="/app.js"></script>  <script src="/announce.js"></script>
+</body></html>