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>

packages/i18n/locales/en.json

@@ -444,7 +444,11 @@
     "OFFER_NOT_AVAILABLE": "This offer isn’t available at the client’s level.",
     "OFFER_LIMIT_REACHED": "The limit for this offer is already used up.",
     "CONCIERGE_SUBSCRIBERS_ONLY": "The personal concierge is for Barev+ and Barev Elite members. For now, write to support — we will help too.",
-    "ASSIGNEE_NO_ACCESS": "This team member has no access to this channel."
+    "ASSIGNEE_NO_ACCESS": "This team member has no access to this channel.",
+    "PROMO_INVALID": "This promo code doesn't exist",
+    "PROMO_EXPIRED": "This promo code is no longer valid",
+    "PROMO_USED": "This promo code has already been used",
+    "PROMO_NOT_FOR_SERVICE": "This promo code doesn't apply to this service"
   },
   "client": {
     "nav": {
@@ -525,7 +529,13 @@
       "cancelPolicy": "Free cancellation and rescheduling up to {{hours}} h before. Later — a {{pct}}% fee.",
       "created": "Order #{{number}} created",
       "extras": "Extras",
-      "add": "Add"
+      "add": "Add",
+      "promo": "Promo code",
+      "promoPlaceholder": "Promo code, if you have one",
+      "promoApply": "Apply",
+      "promoRemove": "Remove",
+      "promoLine": "Promo {{code}} −{{pct}}%",
+      "promoWeaker": "Your membership discount is bigger, so it applies"
     },
     "orders": {
       "title": "My orders",