Walkthroughs: stop autoplaying muted, and show the length

Marty asked why they start muted. Browsers only permit autoplay when a video
is muted, so "expand and play" necessarily meant "expand and play silently" —
and for these that is the wrong trade, because the narration IS the training.
A member's first visit was showing them a silent walkthrough.

So the panel now opens paused with the play button showing. Pressing it is a
user gesture, which means it plays with sound, every time. preload stays
'none' until the panel opens, then goes to 'metadata' so an open panel shows
a real first frame instead of a black rectangle.

Each bar now also carries its runtime ("· 71 sec"), so nobody has to guess
whether they are committing to one minute or ten.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

public/suite-page.html

@@ -72,6 +72,6 @@
   <p class="pg-note"><strong style="color:var(--text)">Teach it forward:</strong> when your two join, walk them through building theirs — a personal page beats a bare link every time. <br>Rebuilding replaces your page at the same link, so anything you've already shared keeps working. Independent team resource · No income is guaranteed · Cryptocurrency involves risk.</p>
 </main>
 <script src="/suite-page.js"></script>
-<script src="/tool-video.js" data-video="/tv/suite-page-builder.mp4" data-title="Watch the Page Builder walkthrough" data-key="page" defer></script>
+<script src="/tool-video.js" data-video="/tv/suite-page-builder.mp4" data-secs="· 42 sec" data-title="Watch the Page Builder walkthrough" data-key="page" defer></script>
 <script src="/chat.js" defer></script>
 <script src="/translate.js" defer></script><script src="/tg-app.js" defer></script><script src="/nav-dash.js" defer></script></body></html>