Order tool v2: step-by-step configurator after mobineko.com/order

User, 19 Oct 2026: build a new version of the order tool like
mobineko.com/order; it should also offer selectable mastering like
brandenburgmastering.com at 60 USD a track.

- New docs/order.html (site /demos/order/): 15-step rail, step panel,
  large live SVG record (colour per disc, translucent, split, splatter,
  marble, colour-in-colour; label, dead wax, jacket view), floating
  quote card with price, ship window and quantity; phone strip and
  bottom bar. Review lists what is missing, itemised quote with basis
  badges, deposit, lead time, ERPNext touchpoints on the simulated
  order. Disabled-not-hidden options with reasons.
- Mastering choice: none, in-house vinyl mastering (5,000 THB a side,
  default), or partner studio (Brandenburg Mastering, Amsterdam, example,
  not contracted) at 60 USD a track (team figure), replacing the in-house
  line.
- Same R list and quote() as artist-order: defaults reproduce 37,836 THB
  per title and the per-copy figures; new lines (repress stamper,
  colour effects, printed inner, finish, obi, bag, shipping) are
  estimates.
- artist-platform.md: the page and the mastering choice; README, landing
  page and site/build.sh entries.
- Checks: pw_order.py 96 checks (parity, partner mastering, 15 steps at
  1440/1024/768/390 dark and light, disabled force-clicks, render sizes
  and fills, uploads, audio readers, share link, place order).

site/public/index.html

@@ -130,6 +130,19 @@ document.documentElement.setAttribute("data-theme",t);})();
         pressed so far, lab and inspection results. Simulated data.</span>
       </a>
     </li>
+    <li>
+      <a href="demos/order/">
+        <strong>Order a record (step by step)</strong>
+        <span>The order tool as a step-by-step configurator: size, discs,
+        vinyl colour and effects, labels, sleeves, jacket and finish,
+        extras, mastering and cutting, test pressings, shipping, track list
+        and artwork, each step with its choices, beside a large live picture
+        of the record that changes with every choice and a running price and
+        ship date. Ends in a review that lists what is still missing and the
+        itemised quote. Indicative demo prices; nothing is uploaded or
+        sent.</span>
+      </a>
+    </li>
     <li>
       <a href="demos/artist-order/">
         <strong>Artist ordering and fan funding</strong>