Plan the artist platform: price calculator and fan-funded pressing

New docs/artist-platform.md: upload master and artwork with automatic
audio, artwork and rights checks; an itemised price calculator for every
customer (per-title vs per-copy lines, price-per-copy curve, lead time
from the production-timeline quote table, versioned price list); and
fan-funded campaigns that press and dropship per fan once the goal is
reached, refund otherwise. Covers goal maths, payments (charge into a
ring-fenced account, CNX as seller of record, legal opinion first; the
Qrates failure as the design rule), repress pre-orders, architecture on
the cnx-factory stack with the public side on a fleet machine, PDPA,
phasing (calculator public early as a run-size probe, campaigns only
after first releases ship), cost and open decisions.

Backlinks from README, process flow, production timeline, revenue model,
digital factory and roadmap items 1 and 20; total investment added-scope
table gains the platform line.

docs/roadmap.md

@@ -18,7 +18,11 @@ These three run in parallel and gate everything downstream:
    per-title services and run size; the tour showed no plating and no
    HVAC anywhere in the incumbent's operation, which is the strongest
    argument yet for pulling galvanics forward from Phase 5. Carry the
-   open run-size question into these conversations.
+   open run-size question into these conversations. The
+   [artist platform](artist-platform.md)'s price calculator, published
+   early with indicative prices and an interest list but no payments,
+   collects that run-size distribution from everyone who configures a
+   record.
 2. **BOI track**: engage a BOI-registered consultant, confirm the activity
    sub-code, and structure the application so the solar, automation, and
    R&D measures stack (see [boi.md](boi.md)). The application precedes
@@ -92,7 +96,9 @@ These three run in parallel and gate everything downstream:
 
 19. First test pressings, QC baselines, reject-rate shakedown
 20. First paying releases; validate turnaround and quality against the
-    regional pitch
+    regional pitch. Fan-funded campaigns on the
+    [artist platform](artist-platform.md) open only after these first
+    releases have shipped and lead times are measured
 21. PVC lab per-lot gate live; begin qualifying Thai/regional compound
     against the European references