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/zh.json

@@ -444,7 +444,11 @@
     "OFFER_NOT_AVAILABLE": "该优惠不适用于客户当前等级。",
     "OFFER_LIMIT_REACHED": "该优惠次数已用完。",
     "CONCIERGE_SUBSCRIBERS_ONLY": "专属礼宾仅面向 Barev+ 和 Barev Elite 会员。目前请联系客服，我们同样会帮你。",
-    "ASSIGNEE_NO_ACCESS": "该成员无权访问此频道。"
+    "ASSIGNEE_NO_ACCESS": "该成员无权访问此频道。",
+    "PROMO_INVALID": "优惠码不存在",
+    "PROMO_EXPIRED": "优惠码已失效",
+    "PROMO_USED": "该优惠码已使用",
+    "PROMO_NOT_FOR_SERVICE": "该优惠码不适用于此服务"
   },
   "client": {
     "nav": {
@@ -525,7 +529,13 @@
       "cancelPolicy": "开始前 {{hours}} 小时以上可免费取消或改期，之后取消将扣除 {{pct}}%。",
       "created": "订单 #{{number}} 已创建",
       "extras": "附加服务",
-      "add": "添加"
+      "add": "添加",
+      "promo": "优惠码",
+      "promoPlaceholder": "如有优惠码请输入",
+      "promoApply": "使用",
+      "promoRemove": "移除",
+      "promoLine": "优惠码 {{code}} −{{pct}}%",
+      "promoWeaker": "会员折扣更大，将使用会员折扣"
     },
     "orders": {
       "title": "我的订单",