Artist ordering demo: configure, check, offer, fan-funded campaign

New static page docs/artist-order.html (test site /demos/artist-order/)
walking the artist platform flow end to end:

- record configurator (format, speed, discs, weight, colour, packaging,
  extras, mastering, test pressings) with a live mock-up
- track list or dropped masters read in the browser (WAV/FLAC/AIFF
  headers, sample peak and clipping), side length against the format,
  jacket and label preflight (size, dpi, CMYK), rights and gate 1
- itemised offer (per title / per copy, pass-through jacket), price per
  copy against quantity, lead time from the production timeline
- direct order or fan-funded campaign: goal = max(minimum run,
  break-even), what the artist keeps, the money rules, a simulated
  campaign (sells out / just makes it / falls short) with refund or
  go-ahead-at-minimum, and the production tracker with the three gates
  and the fan update feed

Price list demo-0.1 splits the doc's 38,000 THB per title and 132 THB per
copy into lines (estimates, each listed with its basis); defaults
reproduce the artist platform example (break-even 41, goal 100, ~548 THB
kept per copy at 100).

artist-platform.md: demo paragraph, side length per format table with
sources, VAT note on the campaign example. README bullet and layout line,
site DEMOS line and landing-page entry.

README.md

@@ -167,6 +167,14 @@ The detail lives in dedicated documents:
   (for artists, labels and any other customer), and optionally launch a
   fan-funded campaign that the plant presses and ships to each fan once
   enough have pre-ordered, with refunds if not
+- [Artist ordering demo](docs/artist-order.html): the artist platform as a
+  clickable single page: configure a record, type the track list or drop
+  the master files and artwork (checked in the browser, never uploaded:
+  format, sample rate, bit depth, clipping, side length against the
+  format, print resolution), approve gate 1, get the itemised offer with
+  its price curve and lead time, then order directly or run a fan-funded
+  campaign to a funded or missed end (refund, or go ahead at the
+  minimum) and follow the production through the three artist gates
 - [Steam and cooling](docs/steam-cooling.html): the utility plant for the
   five-press fleet as a clickable process diagram: water treatment, feed
   tank and heat recovery, a bank of two 500 kg/h boilers, the steam header
@@ -265,6 +273,7 @@ docs/
 │                          schedule (pea/), biomass fuel market
 │                          reports (biomass/)
 ├── suppliers/             Supplier contacts, vendor landscape, supplier map
+├── artist-order.html      Artist ordering and fan-funding demo page
 ├── artist-platform.md     Upload, price calculator, fan-funded pressing
 ├── biomass.md             Biomass fuel strategy and the 60 rai coppice idea
 ├── boi.md                 BOI promotion strategy and requirements