feat: 扫码商品详情页重设计 + 宣传主页 + nginx 路由完善

- public_product_screen: 1:1 复刻设计稿，新增商品介绍、批次防伪（自定义圆形印章）、完整商品参数表、门店营业时间、页脚链接
- app_theme: 完整品牌色系（brand/gray/accent/semantic）
- shop model: 新增 business_hours 字段，public 接口同步返回
- nginx: 新增 /product/ → Flutter app 扫码入口，修复 /docs /download html 后缀兼容
- web/: 新增宣传主页、功能页、文档页、扫码 HTML 及设计资源
- app_shell: 界面优化

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

deploy/nginx-jiu.conf

@@ -7,10 +7,7 @@ server {
     ssl_protocols       TLSv1.2 TLSv1.3;
     ssl_ciphers         HIGH:!aNULL:!MD5;
 
-    root  /opt/jiu/web;
-    index index.html;
-
-    # 商品图片静态文件（^~ 阻止正则 location 拦截 .jpg 等后缀请求）
+    # 商品图片静态文件
     location ^~ /images/ {
         alias /opt/jiu/images/;
         expires 30d;
@@ -25,9 +22,44 @@ server {
         proxy_read_timeout 30s;
     }
 
-    # Flutter SPA fallback
-    location / {
-        try_files $uri $uri/ /index.html;
+    # Flutter 管理端（/app/ 子路径）
+    location /app/ {
+        alias /opt/jiu/web/;
+        index index.html;
+        try_files $uri $uri/ /app/index.html;
+    }
+
+    # Flutter 公开商品扫码页（/product/:id → Flutter app）
+    location /product/ {
+        alias /opt/jiu/web/;
+        try_files $uri /app/index.html;
+    }
+
+    # 营销站点 — 精确路径
+    location = / {
+        root /opt/jiu/marketing;
+        try_files /index.html =404;
+    }
+    location ~ ^/(docs|download)(\.html)?$ {
+        root /opt/jiu/marketing;
+        try_files /$1.html =404;
+    }
+    location /features/ {
+        root /opt/jiu/marketing;
+        try_files $uri $uri.html =404;
+    }
+
+    # 营销站点 — 扫码 HTML 页（保留旧链接兼容）
+    location /scan/ {
+        root /opt/jiu/marketing;
+        try_files /scan.html =404;
+    }
+
+    # 营销静态资源（CSS / SVG / 图片等）
+    location /assets/ {
+        root /opt/jiu/marketing;
+        expires 7d;
+        add_header Cache-Control "public";
     }
 }