Stage 6 (part 2): rest of the client app in the new style, promo code in the order form

Profile with club card, plum theme for buttons/selections and the sticky total,
move screens with the full-width hero, services/docs headers, empty docs fix.
Promo code field: applies to the quote, shows why a code is rejected,
says when the membership discount is bigger.

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>

apps/miniapp-client/src/screens/MoveForm.tsx

@@ -66,8 +66,8 @@ export function MoveForm() {
   );
 
   return (
-    <main className="app">
-      <section className="move-hero">
+    <main className="app app--hero">
+      <section className="hero move-hero">
         <div className="move-hero__label">{me.data?.firstName ? t('client.move.formHello', { name: me.data.firstName }) : t('client.move.title')}</div>
         <div className="move-hero__when">{t('client.move.formTitle')}</div>
         <div className="move-hero__progress">{t('client.move.formSub')}</div>