docs(commercial): one price — $79 Steam DLC rising to $99, subscription retired

Creator ruling 2026-11-01. One SKU, one price, Steam does the selling.

- Pro is a one-time Steam DLC on the free app: $79 introductory, $99 on a stated date, announced
  where the price is shown and actually raised.
- The subscription is retired. The reasoning is in decisions.md: no service behind a monthly fee
  (no servers, no cloud, no content), ~1-3 subscribers per 1,000 installs against 5-8% churn, and
  it carried the most expensive code in the product.
- Polar goes dormant. Its customer-portal design is recorded, not built. The "freemium on Steam,
  convert on Polar, Valve gets nothing" proposal is rejected: in-app purchases must use the Steam
  Wallet, so it risks the listing to save ~$24 a sale.
- Entitlement collapses to `steamDlcOwned`. No lease, no key, no portal, no device limit; the
  greyed tier opens the Steam store overlay, so every purchase stays inside Valve's own surface.
- The site publishes the model and links the store page. It takes no payment and hosts no binaries.
- The $400 lifetime died with the subscription it anchored. Founding 200 died with the coupons and
  passes it needed.

Costs: $115 fixed year one; $79 nets $55.30 after Steam, so three sales cover the year.

docs/ai/decisions.md

@@ -5,6 +5,32 @@ you are about to re-open one of them. **Live commercial rules (prices, entitleme
 signing, support, promo) are in [`commercial.md`](commercial.md)**; the other live rules live in
 the subsystem files. This is the graveyard with cause of death.
 
+## The business model — one price, settled 2026-11-01
+
+**$79 one-time, raising to $99 on a stated date. Sold only on Steam, as a DLC on the free app.**
+The website publishes the model and links the store page; it never takes payment.
+
+**What died the same day:**
+
+- **The subscription.** $10/month for pixels, with no service behind it — no servers, no cloud, no
+  content library, updates free through Steam. Estimated 1–3 subscribers per 1,000 installs, at
+  5–8% monthly churn, against the most expensive code in the product (leases, activations,
+  revocation, portal, dunning). Retired for launch.
+- **Polar as a live rail.** Dormant. Its customer-portal design (`conditions` binding, two
+  activations, 7–14 day lease) is preserved here only so it is not re-derived if a cheaper entry
+  tier is ever justified by real support traffic.
+- **The $400 lifetime** — it was an anchor for a subscription that no longer exists, and above what
+  a beginner pays for a tool with a free incumbent.
+- **Founding 200** — coupons, price locks, earned 30-day passes, founder badges: all machinery for
+  a recurring plan.
+- **Off-Steam conversion of any kind.** The "freemium on Steam, convert on Polar, Valve gets
+  nothing" proposal was rejected: Steamworks requires in-app purchases to use the Steam Wallet, so
+  it is a listing-level risk to save ~$24 a sale.
+
+**Kept:** the free tier is the whole app at a 720p30 output profile, the paid delta is output
+quality only, and the app never sells anything itself — the greyed tier opens the Steam store
+overlay.
+
 ## Commercial mechanics — died 2026-10-31 (same week they were written)
 
 - **The licence "claim page" is dead.** The binding was going to be an OAuth web page that wrote