refactor: 餐线营养秤+餐厅终端导航页PAD居中外壳改造，挂载至根导航

- 9 个营养秤页面（index/01~06，含双屏大/小）统一改造为 body 全屏深色画布 + flex 居中，新增 .device-frame 1280x720 PAD 外壳（圆角24px + 阴影），双屏小屏复用 480x320 .screen-frame
- 修正内容区 calc(100vh - X) → calc(100% - X)，避免视口与外壳尺寸耦合；隐藏 PAD 内可见滚动条
- 父级 canteen-device/index.html 同步改造 + 内容紧凑化（gap/padding/icon）适配 PAD 高度
- 根 index.html SITE_MAP「其他终端 → 餐厅终端设备」标记 done:true 并挂载 9 个营养秤页面，卡片状态由待设计 → 已完成
- 新增 canteen-nutrition-scale/doc/CHANGELOG.md，记录两次改造

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

index.html

@@ -838,7 +838,17 @@ const SITE_MAP = [
     { name:'标准版中心大屏', dir:'other-module/emergency-screen/standard-center', pages:[] },
     { name:'九厂应急中心大屏', dir:'other-module/emergency-screen/jiuchang-center', pages:[] },
     { name:'医疗点PAD端', dir:'other-module/medical-pad', pages:[] },
-    { name:'餐厅终端设备', dir:'other-module/canteen-device', pages:[] }
+    { name:'餐厅终端设备', dir:'other-module/canteen-device', done:true, pages:[
+      {label:'餐线营养秤 · 模块导航', file:'canteen-nutrition-scale/index.html'},
+      {label:'餐线营养秤 · 开餐界面', file:'canteen-nutrition-scale/01-meal-start.html'},
+      {label:'餐线营养秤 · 餐品展示', file:'canteen-nutrition-scale/02-dish-display.html'},
+      {label:'餐线营养秤 · 取餐（单屏）', file:'canteen-nutrition-scale/03-meal-pickup.html'},
+      {label:'餐线营养秤 · 取餐（双屏·大屏）', file:'canteen-nutrition-scale/03-meal-pickup-dual-large.html'},
+      {label:'餐线营养秤 · 取餐（双屏·小屏）', file:'canteen-nutrition-scale/03-meal-pickup-dual-small.html'},
+      {label:'餐线营养秤 · 设置', file:'canteen-nutrition-scale/04-settings.html'},
+      {label:'餐线营养秤 · 餐品采样', file:'canteen-nutrition-scale/05-dish-sampling.html'},
+      {label:'餐线营养秤 · 采样历史', file:'canteen-nutrition-scale/06-sampling-history.html'}
+    ] }
   ]}
 ];