feat(pricing): the server prices app orders with legacy's making-charge formula (MON-08)

Legacy: final % = variant % + customer % − the largest active promotion
on the product, its category or its brand; rial charge 0. The apps sent
the variant's own % only, so the new app undercharged by the customer's
percent (usually 3) and ignored promotions, and the server trusted
whatever the app sent.

- pricing/wage-formula.ts: one formula, legacy by default, with
  coefficients, promotion pick, constant, floor/cap and rounding so the
  admin screen can change it; validated
- an app order is priced by it; the app's wage, discount and rial charge
  are ignored; an operator's manual numbers are kept
- POST customer/me/wage-quote; both apps show that figure
- admin/pricing/wage-formula (config.wage): read, preview, approve with
  the sample it was checked on, last 20 versions kept; the setting is
  kept off the generic const routes

Owner approval: 2026-10-08.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

apps/user-app-v2/src/views/CartView.vue

@@ -222,6 +222,8 @@ const submitOrder = async () => {
         return {
           productVariantId: item.vid,
           quantity: item.qty,
+          // Sent for older API builds only: the server prices app orders itself
+          // (MON-08) and ignores this figure.
           wagePercent: variant ? parseFloat(variant.defaultWagePercent) : 0,
         }
       }),